aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/networking
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/00-INDEX116
-rw-r--r--Documentation/networking/bonding.txt31
-rw-r--r--Documentation/networking/dmfe.txt3
-rw-r--r--Documentation/networking/ifenslave.c18
-rw-r--r--Documentation/networking/ip-sysctl.txt35
-rw-r--r--Documentation/networking/netdev-features.txt154
-rw-r--r--Documentation/networking/nfc.txt128
-rw-r--r--Documentation/networking/scaling.txt378
-rw-r--r--Documentation/networking/stmmac.txt200
9 files changed, 969 insertions, 94 deletions
diff --git a/Documentation/networking/00-INDEX b/Documentation/networking/00-INDEX
index 4edd78dfb36..bbce1215434 100644
--- a/Documentation/networking/00-INDEX
+++ b/Documentation/networking/00-INDEX
@@ -1,13 +1,21 @@
100-INDEX 100-INDEX
2 - this file 2 - this file
33c359.txt
4 - information on the 3Com TokenLink Velocity XL (3c5359) driver.
33c505.txt 53c505.txt
4 - information on the 3Com EtherLink Plus (3c505) driver. 6 - information on the 3Com EtherLink Plus (3c505) driver.
73c509.txt
8 - information on the 3Com Etherlink III Series Ethernet cards.
56pack.txt 96pack.txt
6 - info on the 6pack protocol, an alternative to KISS for AX.25 10 - info on the 6pack protocol, an alternative to KISS for AX.25
7DLINK.txt 11DLINK.txt
8 - info on the D-Link DE-600/DE-620 parallel port pocket adapters 12 - info on the D-Link DE-600/DE-620 parallel port pocket adapters
9PLIP.txt 13PLIP.txt
10 - PLIP: The Parallel Line Internet Protocol device driver 14 - PLIP: The Parallel Line Internet Protocol device driver
15README.ipw2100
16 - README for the Intel PRO/Wireless 2100 driver.
17README.ipw2200
18 - README for the Intel PRO/Wireless 2915ABG and 2200BG driver.
11README.sb1000 19README.sb1000
12 - info on General Instrument/NextLevel SURFboard1000 cable modem. 20 - info on General Instrument/NextLevel SURFboard1000 cable modem.
13alias.txt 21alias.txt
@@ -20,8 +28,12 @@ atm.txt
20 - info on where to get ATM programs and support for Linux. 28 - info on where to get ATM programs and support for Linux.
21ax25.txt 29ax25.txt
22 - info on using AX.25 and NET/ROM code for Linux 30 - info on using AX.25 and NET/ROM code for Linux
31batman-adv.txt
32 - B.A.T.M.A.N routing protocol on top of layer 2 Ethernet Frames.
23baycom.txt 33baycom.txt
24 - info on the driver for Baycom style amateur radio modems 34 - info on the driver for Baycom style amateur radio modems
35bonding.txt
36 - Linux Ethernet Bonding Driver HOWTO: link aggregation in Linux.
25bridge.txt 37bridge.txt
26 - where to get user space programs for ethernet bridging with Linux. 38 - where to get user space programs for ethernet bridging with Linux.
27can.txt 39can.txt
@@ -34,32 +46,60 @@ cxacru.txt
34 - Conexant AccessRunner USB ADSL Modem 46 - Conexant AccessRunner USB ADSL Modem
35cxacru-cf.py 47cxacru-cf.py
36 - Conexant AccessRunner USB ADSL Modem configuration file parser 48 - Conexant AccessRunner USB ADSL Modem configuration file parser
49cxgb.txt
50 - Release Notes for the Chelsio N210 Linux device driver.
51dccp.txt
52 - the Datagram Congestion Control Protocol (DCCP) (RFC 4340..42).
37de4x5.txt 53de4x5.txt
38 - the Digital EtherWORKS DE4?? and DE5?? PCI Ethernet driver 54 - the Digital EtherWORKS DE4?? and DE5?? PCI Ethernet driver
39decnet.txt 55decnet.txt
40 - info on using the DECnet networking layer in Linux. 56 - info on using the DECnet networking layer in Linux.
41depca.txt 57depca.txt
42 - the Digital DEPCA/EtherWORKS DE1?? and DE2?? LANCE Ethernet driver 58 - the Digital DEPCA/EtherWORKS DE1?? and DE2?? LANCE Ethernet driver
59dl2k.txt
60 - README for D-Link DL2000-based Gigabit Ethernet Adapters (dl2k.ko).
61dm9000.txt
62 - README for the Simtec DM9000 Network driver.
43dmfe.txt 63dmfe.txt
44 - info on the Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver. 64 - info on the Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver.
65dns_resolver.txt
66 - The DNS resolver module allows kernel servies to make DNS queries.
67driver.txt
68 - Softnet driver issues.
45e100.txt 69e100.txt
46 - info on Intel's EtherExpress PRO/100 line of 10/100 boards 70 - info on Intel's EtherExpress PRO/100 line of 10/100 boards
47e1000.txt 71e1000.txt
48 - info on Intel's E1000 line of gigabit ethernet boards 72 - info on Intel's E1000 line of gigabit ethernet boards
73e1000e.txt
74 - README for the Intel Gigabit Ethernet Driver (e1000e).
49eql.txt 75eql.txt
50 - serial IP load balancing 76 - serial IP load balancing
51ewrk3.txt 77ewrk3.txt
52 - the Digital EtherWORKS 3 DE203/4/5 Ethernet driver 78 - the Digital EtherWORKS 3 DE203/4/5 Ethernet driver
79fib_trie.txt
80 - Level Compressed Trie (LC-trie) notes: a structure for routing.
53filter.txt 81filter.txt
54 - Linux Socket Filtering 82 - Linux Socket Filtering
55fore200e.txt 83fore200e.txt
56 - FORE Systems PCA-200E/SBA-200E ATM NIC driver info. 84 - FORE Systems PCA-200E/SBA-200E ATM NIC driver info.
57framerelay.txt 85framerelay.txt
58 - info on using Frame Relay/Data Link Connection Identifier (DLCI). 86 - info on using Frame Relay/Data Link Connection Identifier (DLCI).
87gen_stats.txt
88 - Generic networking statistics for netlink users.
89generic_hdlc.txt
90 - The generic High Level Data Link Control (HDLC) layer.
59generic_netlink.txt 91generic_netlink.txt
60 - info on Generic Netlink 92 - info on Generic Netlink
93gianfar.txt
94 - Gianfar Ethernet Driver.
61ieee802154.txt 95ieee802154.txt
62 - Linux IEEE 802.15.4 implementation, API and drivers 96 - Linux IEEE 802.15.4 implementation, API and drivers
97ifenslave.c
98 - Configure network interfaces for parallel routing (bonding).
99igb.txt
100 - README for the Intel Gigabit Ethernet Driver (igb).
101igbvf.txt
102 - README for the Intel Gigabit Ethernet Driver (igbvf).
63ip-sysctl.txt 103ip-sysctl.txt
64 - /proc/sys/net/ipv4/* variables 104 - /proc/sys/net/ipv4/* variables
65ip_dynaddr.txt 105ip_dynaddr.txt
@@ -68,41 +108,117 @@ ipddp.txt
68 - AppleTalk-IP Decapsulation and AppleTalk-IP Encapsulation 108 - AppleTalk-IP Decapsulation and AppleTalk-IP Encapsulation
69iphase.txt 109iphase.txt
70 - Interphase PCI ATM (i)Chip IA Linux driver info. 110 - Interphase PCI ATM (i)Chip IA Linux driver info.
111ipv6.txt
112 - Options to the ipv6 kernel module.
113ipvs-sysctl.txt
114 - Per-inode explanation of the /proc/sys/net/ipv4/vs interface.
71irda.txt 115irda.txt
72 - where to get IrDA (infrared) utilities and info for Linux. 116 - where to get IrDA (infrared) utilities and info for Linux.
117ixgb.txt
118 - README for the Intel 10 Gigabit Ethernet Driver (ixgb).
119ixgbe.txt
120 - README for the Intel 10 Gigabit Ethernet Driver (ixgbe).
121ixgbevf.txt
122 - README for the Intel Virtual Function (VF) Driver (ixgbevf).
123l2tp.txt
124 - User guide to the L2TP tunnel protocol.
73lapb-module.txt 125lapb-module.txt
74 - programming information of the LAPB module. 126 - programming information of the LAPB module.
75ltpc.txt 127ltpc.txt
76 - the Apple or Farallon LocalTalk PC card driver 128 - the Apple or Farallon LocalTalk PC card driver
129mac80211-injection.txt
130 - HOWTO use packet injection with mac80211
77multicast.txt 131multicast.txt
78 - Behaviour of cards under Multicast 132 - Behaviour of cards under Multicast
133multiqueue.txt
134 - HOWTO for multiqueue network device support.
135netconsole.txt
136 - The network console module netconsole.ko: configuration and notes.
137netdev-features.txt
138 - Network interface features API description.
79netdevices.txt 139netdevices.txt
80 - info on network device driver functions exported to the kernel. 140 - info on network device driver functions exported to the kernel.
141netif-msg.txt
142 - Design of the network interface message level setting (NETIF_MSG_*).
143nfc.txt
144 - The Linux Near Field Communication (NFS) subsystem.
81olympic.txt 145olympic.txt
82 - IBM PCI Pit/Pit-Phy/Olympic Token Ring driver info. 146 - IBM PCI Pit/Pit-Phy/Olympic Token Ring driver info.
147operstates.txt
148 - Overview of network interface operational states.
149packet_mmap.txt
150 - User guide to memory mapped packet socket rings (PACKET_[RT]X_RING).
151phonet.txt
152 - The Phonet packet protocol used in Nokia cellular modems.
153phy.txt
154 - The PHY abstraction layer.
155pktgen.txt
156 - User guide to the kernel packet generator (pktgen.ko).
83policy-routing.txt 157policy-routing.txt
84 - IP policy-based routing 158 - IP policy-based routing
159ppp_generic.txt
160 - Information about the generic PPP driver.
161proc_net_tcp.txt
162 - Per inode overview of the /proc/net/tcp and /proc/net/tcp6 interfaces.
163radiotap-headers.txt
164 - Background on radiotap headers.
85ray_cs.txt 165ray_cs.txt
86 - Raylink Wireless LAN card driver info. 166 - Raylink Wireless LAN card driver info.
167rds.txt
168 - Background on the reliable, ordered datagram delivery method RDS.
169regulatory.txt
170 - Overview of the Linux wireless regulatory infrastructure.
171rxrpc.txt
172 - Guide to the RxRPC protocol.
173s2io.txt
174 - Release notes for Neterion Xframe I/II 10GbE driver.
175scaling.txt
176 - Explanation of network scaling techniques: RSS, RPS, RFS, aRFS, XPS.
177sctp.txt
178 - Notes on the Linux kernel implementation of the SCTP protocol.
179secid.txt
180 - Explanation of the secid member in flow structures.
87skfp.txt 181skfp.txt
88 - SysKonnect FDDI (SK-5xxx, Compaq Netelligent) driver info. 182 - SysKonnect FDDI (SK-5xxx, Compaq Netelligent) driver info.
89smc9.txt 183smc9.txt
90 - the driver for SMC's 9000 series of Ethernet cards 184 - the driver for SMC's 9000 series of Ethernet cards
91smctr.txt 185smctr.txt
92 - SMC TokenCard TokenRing Linux driver info. 186 - SMC TokenCard TokenRing Linux driver info.
187spider-net.txt
188 - README for the Spidernet Driver (as found in PS3 / Cell BE).
189stmmac.txt
190 - README for the STMicro Synopsys Ethernet driver.
191tc-actions-env-rules.txt
192 - rules for traffic control (tc) actions.
193timestamping.txt
194 - overview of network packet timestamping variants.
93tcp.txt 195tcp.txt
94 - short blurb on how TCP output takes place. 196 - short blurb on how TCP output takes place.
197tcp-thin.txt
198 - kernel tuning options for low rate 'thin' TCP streams.
95tlan.txt 199tlan.txt
96 - ThunderLAN (Compaq Netelligent 10/100, Olicom OC-2xxx) driver info. 200 - ThunderLAN (Compaq Netelligent 10/100, Olicom OC-2xxx) driver info.
97tms380tr.txt 201tms380tr.txt
98 - SysKonnect Token Ring ISA/PCI adapter driver info. 202 - SysKonnect Token Ring ISA/PCI adapter driver info.
203tproxy.txt
204 - Transparent proxy support user guide.
99tuntap.txt 205tuntap.txt
100 - TUN/TAP device driver, allowing user space Rx/Tx of packets. 206 - TUN/TAP device driver, allowing user space Rx/Tx of packets.
207udplite.txt
208 - UDP-Lite protocol (RFC 3828) introduction.
101vortex.txt 209vortex.txt
102 - info on using 3Com Vortex (3c590, 3c592, 3c595, 3c597) Ethernet cards. 210 - info on using 3Com Vortex (3c590, 3c592, 3c595, 3c597) Ethernet cards.
211vxge.txt
212 - README for the Neterion X3100 PCIe Server Adapter.
103x25.txt 213x25.txt
104 - general info on X.25 development. 214 - general info on X.25 development.
105x25-iface.txt 215x25-iface.txt
106 - description of the X.25 Packet Layer to LAPB device interface. 216 - description of the X.25 Packet Layer to LAPB device interface.
217xfrm_proc.txt
218 - description of the statistics package for XFRM.
219xfrm_sync.txt
220 - sync patches for XFRM enable migration of an SA between hosts.
221xfrm_sysctl.txt
222 - description of the XFRM configuration options.
107z8530drv.txt 223z8530drv.txt
108 - info about Linux driver for Z8530 based HDLC cards for AX.25 224 - info about Linux driver for Z8530 based HDLC cards for AX.25
diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 675612ff41a..91df678fb7f 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -238,6 +238,18 @@ ad_select
238 238
239 This option was added in bonding version 3.4.0. 239 This option was added in bonding version 3.4.0.
240 240
241all_slaves_active
242
243 Specifies that duplicate frames (received on inactive ports) should be
244 dropped (0) or delivered (1).
245
246 Normally, bonding will drop duplicate frames (received on inactive
247 ports), which is desirable for most users. But there are some times
248 it is nice to allow duplicate frames to be delivered.
249
250 The default value is 0 (drop duplicate frames received on inactive
251 ports).
252
241arp_interval 253arp_interval
242 254
243 Specifies the ARP link monitoring frequency in milliseconds. 255 Specifies the ARP link monitoring frequency in milliseconds.
@@ -433,6 +445,23 @@ miimon
433 determined. See the High Availability section for additional 445 determined. See the High Availability section for additional
434 information. The default value is 0. 446 information. The default value is 0.
435 447
448min_links
449
450 Specifies the minimum number of links that must be active before
451 asserting carrier. It is similar to the Cisco EtherChannel min-links
452 feature. This allows setting the minimum number of member ports that
453 must be up (link-up state) before marking the bond device as up
454 (carrier on). This is useful for situations where higher level services
455 such as clustering want to ensure a minimum number of low bandwidth
456 links are active before switchover. This option only affect 802.3ad
457 mode.
458
459 The default value is 0. This will cause carrier to be asserted (for
460 802.3ad mode) whenever there is an active aggregator, regardless of the
461 number of available links in that aggregator. Note that, because an
462 aggregator cannot be active without at least one available link,
463 setting this option to 0 or to 1 has the exact same effect.
464
436mode 465mode
437 466
438 Specifies one of the bonding policies. The default is 467 Specifies one of the bonding policies. The default is
@@ -599,7 +628,7 @@ num_unsol_na
599 affect only the active-backup mode. These options were added for 628 affect only the active-backup mode. These options were added for
600 bonding versions 3.3.0 and 3.4.0 respectively. 629 bonding versions 3.3.0 and 3.4.0 respectively.
601 630
602 From Linux 2.6.40 and bonding version 3.7.1, these notifications 631 From Linux 3.0 and bonding version 3.7.1, these notifications
603 are generated by the ipv4 and ipv6 code and the numbers of 632 are generated by the ipv4 and ipv6 code and the numbers of
604 repetitions cannot be set independently. 633 repetitions cannot be set independently.
605 634
diff --git a/Documentation/networking/dmfe.txt b/Documentation/networking/dmfe.txt
index 8006c227fda..25320bf19c8 100644
--- a/Documentation/networking/dmfe.txt
+++ b/Documentation/networking/dmfe.txt
@@ -1,3 +1,5 @@
1Note: This driver doesn't have a maintainer.
2
1Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver for Linux. 3Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver for Linux.
2 4
3This program is free software; you can redistribute it and/or 5This program is free software; you can redistribute it and/or
@@ -55,7 +57,6 @@ Test and make sure PCI latency is now correct for all cases.
55Authors: 57Authors:
56 58
57Sten Wang <sten_wang@davicom.com.tw > : Original Author 59Sten Wang <sten_wang@davicom.com.tw > : Original Author
58Tobias Ringstrom <tori@unhappy.mine.nu> : Current Maintainer
59 60
60Contributors: 61Contributors:
61 62
diff --git a/Documentation/networking/ifenslave.c b/Documentation/networking/ifenslave.c
index 2bac9618c34..65968fbf1e4 100644
--- a/Documentation/networking/ifenslave.c
+++ b/Documentation/networking/ifenslave.c
@@ -260,7 +260,7 @@ int main(int argc, char *argv[])
260 case 'V': opt_V++; exclusive++; break; 260 case 'V': opt_V++; exclusive++; break;
261 261
262 case '?': 262 case '?':
263 fprintf(stderr, usage_msg); 263 fprintf(stderr, "%s", usage_msg);
264 res = 2; 264 res = 2;
265 goto out; 265 goto out;
266 } 266 }
@@ -268,13 +268,13 @@ int main(int argc, char *argv[])
268 268
269 /* options check */ 269 /* options check */
270 if (exclusive > 1) { 270 if (exclusive > 1) {
271 fprintf(stderr, usage_msg); 271 fprintf(stderr, "%s", usage_msg);
272 res = 2; 272 res = 2;
273 goto out; 273 goto out;
274 } 274 }
275 275
276 if (opt_v || opt_V) { 276 if (opt_v || opt_V) {
277 printf(version); 277 printf("%s", version);
278 if (opt_V) { 278 if (opt_V) {
279 res = 0; 279 res = 0;
280 goto out; 280 goto out;
@@ -282,14 +282,14 @@ int main(int argc, char *argv[])
282 } 282 }
283 283
284 if (opt_u) { 284 if (opt_u) {
285 printf(usage_msg); 285 printf("%s", usage_msg);
286 res = 0; 286 res = 0;
287 goto out; 287 goto out;
288 } 288 }
289 289
290 if (opt_h) { 290 if (opt_h) {
291 printf(usage_msg); 291 printf("%s", usage_msg);
292 printf(help_msg); 292 printf("%s", help_msg);
293 res = 0; 293 res = 0;
294 goto out; 294 goto out;
295 } 295 }
@@ -309,7 +309,7 @@ int main(int argc, char *argv[])
309 goto out; 309 goto out;
310 } else { 310 } else {
311 /* Just show usage */ 311 /* Just show usage */
312 fprintf(stderr, usage_msg); 312 fprintf(stderr, "%s", usage_msg);
313 res = 2; 313 res = 2;
314 goto out; 314 goto out;
315 } 315 }
@@ -320,7 +320,7 @@ int main(int argc, char *argv[])
320 master_ifname = *spp++; 320 master_ifname = *spp++;
321 321
322 if (master_ifname == NULL) { 322 if (master_ifname == NULL) {
323 fprintf(stderr, usage_msg); 323 fprintf(stderr, "%s", usage_msg);
324 res = 2; 324 res = 2;
325 goto out; 325 goto out;
326 } 326 }
@@ -339,7 +339,7 @@ int main(int argc, char *argv[])
339 339
340 if (slave_ifname == NULL) { 340 if (slave_ifname == NULL) {
341 if (opt_d || opt_c) { 341 if (opt_d || opt_c) {
342 fprintf(stderr, usage_msg); 342 fprintf(stderr, "%s", usage_msg);
343 res = 2; 343 res = 2;
344 goto out; 344 goto out;
345 } 345 }
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index bfe924217f2..ca5cdcd0f0e 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -106,16 +106,6 @@ inet_peer_maxttl - INTEGER
106 when the number of entries in the pool is very small). 106 when the number of entries in the pool is very small).
107 Measured in seconds. 107 Measured in seconds.
108 108
109inet_peer_gc_mintime - INTEGER
110 Minimum interval between garbage collection passes. This interval is
111 in effect under high memory pressure on the pool.
112 Measured in seconds.
113
114inet_peer_gc_maxtime - INTEGER
115 Minimum interval between garbage collection passes. This interval is
116 in effect under low (or absent) memory pressure on the pool.
117 Measured in seconds.
118
119TCP variables: 109TCP variables:
120 110
121somaxconn - INTEGER 111somaxconn - INTEGER
@@ -394,7 +384,7 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max
394 min: Minimal size of receive buffer used by TCP sockets. 384 min: Minimal size of receive buffer used by TCP sockets.
395 It is guaranteed to each TCP socket, even under moderate memory 385 It is guaranteed to each TCP socket, even under moderate memory
396 pressure. 386 pressure.
397 Default: 8K 387 Default: 1 page
398 388
399 default: initial size of receive buffer used by TCP sockets. 389 default: initial size of receive buffer used by TCP sockets.
400 This value overrides net.core.rmem_default used by other protocols. 390 This value overrides net.core.rmem_default used by other protocols.
@@ -483,7 +473,7 @@ tcp_window_scaling - BOOLEAN
483tcp_wmem - vector of 3 INTEGERs: min, default, max 473tcp_wmem - vector of 3 INTEGERs: min, default, max
484 min: Amount of memory reserved for send buffers for TCP sockets. 474 min: Amount of memory reserved for send buffers for TCP sockets.
485 Each TCP socket has rights to use it due to fact of its birth. 475 Each TCP socket has rights to use it due to fact of its birth.
486 Default: 4K 476 Default: 1 page
487 477
488 default: initial size of send buffer used by TCP sockets. This 478 default: initial size of send buffer used by TCP sockets. This
489 value overrides net.core.wmem_default used by other protocols. 479 value overrides net.core.wmem_default used by other protocols.
@@ -553,13 +543,13 @@ udp_rmem_min - INTEGER
553 Minimal size of receive buffer used by UDP sockets in moderation. 543 Minimal size of receive buffer used by UDP sockets in moderation.
554 Each UDP socket is able to use the size for receiving data, even if 544 Each UDP socket is able to use the size for receiving data, even if
555 total pages of UDP sockets exceed udp_mem pressure. The unit is byte. 545 total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
556 Default: 4096 546 Default: 1 page
557 547
558udp_wmem_min - INTEGER 548udp_wmem_min - INTEGER
559 Minimal size of send buffer used by UDP sockets in moderation. 549 Minimal size of send buffer used by UDP sockets in moderation.
560 Each UDP socket is able to use the size for sending data, even if 550 Each UDP socket is able to use the size for sending data, even if
561 total pages of UDP sockets exceed udp_mem pressure. The unit is byte. 551 total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
562 Default: 4096 552 Default: 1 page
563 553
564CIPSOv4 Variables: 554CIPSOv4 Variables:
565 555
@@ -1002,7 +992,7 @@ bindv6only - BOOLEAN
1002 TRUE: disable IPv4-mapped address feature 992 TRUE: disable IPv4-mapped address feature
1003 FALSE: enable IPv4-mapped address feature 993 FALSE: enable IPv4-mapped address feature
1004 994
1005 Default: FALSE (as specified in RFC2553bis) 995 Default: FALSE (as specified in RFC3493)
1006 996
1007IPv6 Fragmentation: 997IPv6 Fragmentation:
1008 998
@@ -1052,7 +1042,7 @@ conf/interface/*:
1052 The functional behaviour for certain settings is different 1042 The functional behaviour for certain settings is different
1053 depending on whether local forwarding is enabled or not. 1043 depending on whether local forwarding is enabled or not.
1054 1044
1055accept_ra - BOOLEAN 1045accept_ra - INTEGER
1056 Accept Router Advertisements; autoconfigure using them. 1046 Accept Router Advertisements; autoconfigure using them.
1057 1047
1058 Possible values are: 1048 Possible values are:
@@ -1116,7 +1106,7 @@ dad_transmits - INTEGER
1116 The amount of Duplicate Address Detection probes to send. 1106 The amount of Duplicate Address Detection probes to send.
1117 Default: 1 1107 Default: 1
1118 1108
1119forwarding - BOOLEAN 1109forwarding - INTEGER
1120 Configure interface-specific Host/Router behaviour. 1110 Configure interface-specific Host/Router behaviour.
1121 1111
1122 Note: It is recommended to have the same setting on all 1112 Note: It is recommended to have the same setting on all
@@ -1465,10 +1455,17 @@ sctp_mem - vector of 3 INTEGERs: min, pressure, max
1465 Default is calculated at boot time from amount of available memory. 1455 Default is calculated at boot time from amount of available memory.
1466 1456
1467sctp_rmem - vector of 3 INTEGERs: min, default, max 1457sctp_rmem - vector of 3 INTEGERs: min, default, max
1468 See tcp_rmem for a description. 1458 Only the first value ("min") is used, "default" and "max" are
1459 ignored.
1460
1461 min: Minimal size of receive buffer used by SCTP socket.
1462 It is guaranteed to each SCTP socket (but not association) even
1463 under moderate memory pressure.
1464
1465 Default: 1 page
1469 1466
1470sctp_wmem - vector of 3 INTEGERs: min, default, max 1467sctp_wmem - vector of 3 INTEGERs: min, default, max
1471 See tcp_wmem for a description. 1468 Currently this tunable has no effect.
1472 1469
1473addr_scope_policy - INTEGER 1470addr_scope_policy - INTEGER
1474 Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00 1471 Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00
diff --git a/Documentation/networking/netdev-features.txt b/Documentation/networking/netdev-features.txt
new file mode 100644
index 00000000000..4b1c0dcef84
--- /dev/null
+++ b/Documentation/networking/netdev-features.txt
@@ -0,0 +1,154 @@
1Netdev features mess and how to get out from it alive
2=====================================================
3
4Author:
5 Michał Mirosław <mirq-linux@rere.qmqm.pl>
6
7
8
9 Part I: Feature sets
10======================
11
12Long gone are the days when a network card would just take and give packets
13verbatim. Today's devices add multiple features and bugs (read: offloads)
14that relieve an OS of various tasks like generating and checking checksums,
15splitting packets, classifying them. Those capabilities and their state
16are commonly referred to as netdev features in Linux kernel world.
17
18There are currently three sets of features relevant to the driver, and
19one used internally by network core:
20
21 1. netdev->hw_features set contains features whose state may possibly
22 be changed (enabled or disabled) for a particular device by user's
23 request. This set should be initialized in ndo_init callback and not
24 changed later.
25
26 2. netdev->features set contains features which are currently enabled
27 for a device. This should be changed only by network core or in
28 error paths of ndo_set_features callback.
29
30 3. netdev->vlan_features set contains features whose state is inherited
31 by child VLAN devices (limits netdev->features set). This is currently
32 used for all VLAN devices whether tags are stripped or inserted in
33 hardware or software.
34
35 4. netdev->wanted_features set contains feature set requested by user.
36 This set is filtered by ndo_fix_features callback whenever it or
37 some device-specific conditions change. This set is internal to
38 networking core and should not be referenced in drivers.
39
40
41
42 Part II: Controlling enabled features
43=======================================
44
45When current feature set (netdev->features) is to be changed, new set
46is calculated and filtered by calling ndo_fix_features callback
47and netdev_fix_features(). If the resulting set differs from current
48set, it is passed to ndo_set_features callback and (if the callback
49returns success) replaces value stored in netdev->features.
50NETDEV_FEAT_CHANGE notification is issued after that whenever current
51set might have changed.
52
53The following events trigger recalculation:
54 1. device's registration, after ndo_init returned success
55 2. user requested changes in features state
56 3. netdev_update_features() is called
57
58ndo_*_features callbacks are called with rtnl_lock held. Missing callbacks
59are treated as always returning success.
60
61A driver that wants to trigger recalculation must do so by calling
62netdev_update_features() while holding rtnl_lock. This should not be done
63from ndo_*_features callbacks. netdev->features should not be modified by
64driver except by means of ndo_fix_features callback.
65
66
67
68 Part III: Implementation hints
69================================
70
71 * ndo_fix_features:
72
73All dependencies between features should be resolved here. The resulting
74set can be reduced further by networking core imposed limitations (as coded
75in netdev_fix_features()). For this reason it is safer to disable a feature
76when its dependencies are not met instead of forcing the dependency on.
77
78This callback should not modify hardware nor driver state (should be
79stateless). It can be called multiple times between successive
80ndo_set_features calls.
81
82Callback must not alter features contained in NETIF_F_SOFT_FEATURES or
83NETIF_F_NEVER_CHANGE sets. The exception is NETIF_F_VLAN_CHALLENGED but
84care must be taken as the change won't affect already configured VLANs.
85
86 * ndo_set_features:
87
88Hardware should be reconfigured to match passed feature set. The set
89should not be altered unless some error condition happens that can't
90be reliably detected in ndo_fix_features. In this case, the callback
91should update netdev->features to match resulting hardware state.
92Errors returned are not (and cannot be) propagated anywhere except dmesg.
93(Note: successful return is zero, >0 means silent error.)
94
95
96
97 Part IV: Features
98===================
99
100For current list of features, see include/linux/netdev_features.h.
101This section describes semantics of some of them.
102
103 * Transmit checksumming
104
105For complete description, see comments near the top of include/linux/skbuff.h.
106
107Note: NETIF_F_HW_CSUM is a superset of NETIF_F_IP_CSUM + NETIF_F_IPV6_CSUM.
108It means that device can fill TCP/UDP-like checksum anywhere in the packets
109whatever headers there might be.
110
111 * Transmit TCP segmentation offload
112
113NETIF_F_TSO_ECN means that hardware can properly split packets with CWR bit
114set, be it TCPv4 (when NETIF_F_TSO is enabled) or TCPv6 (NETIF_F_TSO6).
115
116 * Transmit DMA from high memory
117
118On platforms where this is relevant, NETIF_F_HIGHDMA signals that
119ndo_start_xmit can handle skbs with frags in high memory.
120
121 * Transmit scatter-gather
122
123Those features say that ndo_start_xmit can handle fragmented skbs:
124NETIF_F_SG --- paged skbs (skb_shinfo()->frags), NETIF_F_FRAGLIST ---
125chained skbs (skb->next/prev list).
126
127 * Software features
128
129Features contained in NETIF_F_SOFT_FEATURES are features of networking
130stack. Driver should not change behaviour based on them.
131
132 * LLTX driver (deprecated for hardware drivers)
133
134NETIF_F_LLTX should be set in drivers that implement their own locking in
135transmit path or don't need locking at all (e.g. software tunnels).
136In ndo_start_xmit, it is recommended to use a try_lock and return
137NETDEV_TX_LOCKED when the spin lock fails. The locking should also properly
138protect against other callbacks (the rules you need to find out).
139
140Don't use it for new drivers.
141
142 * netns-local device
143
144NETIF_F_NETNS_LOCAL is set for devices that are not allowed to move between
145network namespaces (e.g. loopback).
146
147Don't use it in drivers.
148
149 * VLAN challenged
150
151NETIF_F_VLAN_CHALLENGED should be set for devices which can't cope with VLAN
152headers. Some drivers set this because the cards can't handle the bigger MTU.
153[FIXME: Those cases could be fixed in VLAN code by allowing only reduced-MTU
154VLANs. This may be not useful, though.]
diff --git a/Documentation/networking/nfc.txt b/Documentation/networking/nfc.txt
new file mode 100644
index 00000000000..b24c29bdae2
--- /dev/null
+++ b/Documentation/networking/nfc.txt
@@ -0,0 +1,128 @@
1Linux NFC subsystem
2===================
3
4The Near Field Communication (NFC) subsystem is required to standardize the
5NFC device drivers development and to create an unified userspace interface.
6
7This document covers the architecture overview, the device driver interface
8description and the userspace interface description.
9
10Architecture overview
11---------------------
12
13The NFC subsystem is responsible for:
14 - NFC adapters management;
15 - Polling for targets;
16 - Low-level data exchange;
17
18The subsystem is divided in some parts. The 'core' is responsible for
19providing the device driver interface. On the other side, it is also
20responsible for providing an interface to control operations and low-level
21data exchange.
22
23The control operations are available to userspace via generic netlink.
24
25The low-level data exchange interface is provided by the new socket family
26PF_NFC. The NFC_SOCKPROTO_RAW performs raw communication with NFC targets.
27
28
29 +--------------------------------------+
30 | USER SPACE |
31 +--------------------------------------+
32 ^ ^
33 | low-level | control
34 | data exchange | operations
35 | |
36 | v
37 | +-----------+
38 | AF_NFC | netlink |
39 | socket +-----------+
40 | raw ^
41 | |
42 v v
43 +---------+ +-----------+
44 | rawsock | <--------> | core |
45 +---------+ +-----------+
46 ^
47 |
48 v
49 +-----------+
50 | driver |
51 +-----------+
52
53Device Driver Interface
54-----------------------
55
56When registering on the NFC subsystem, the device driver must inform the core
57of the set of supported NFC protocols and the set of ops callbacks. The ops
58callbacks that must be implemented are the following:
59
60* start_poll - setup the device to poll for targets
61* stop_poll - stop on progress polling operation
62* activate_target - select and initialize one of the targets found
63* deactivate_target - deselect and deinitialize the selected target
64* data_exchange - send data and receive the response (transceive operation)
65
66Userspace interface
67--------------------
68
69The userspace interface is divided in control operations and low-level data
70exchange operation.
71
72CONTROL OPERATIONS:
73
74Generic netlink is used to implement the interface to the control operations.
75The operations are composed by commands and events, all listed below:
76
77* NFC_CMD_GET_DEVICE - get specific device info or dump the device list
78* NFC_CMD_START_POLL - setup a specific device to polling for targets
79* NFC_CMD_STOP_POLL - stop the polling operation in a specific device
80* NFC_CMD_GET_TARGET - dump the list of targets found by a specific device
81
82* NFC_EVENT_DEVICE_ADDED - reports an NFC device addition
83* NFC_EVENT_DEVICE_REMOVED - reports an NFC device removal
84* NFC_EVENT_TARGETS_FOUND - reports START_POLL results when 1 or more targets
85are found
86
87The user must call START_POLL to poll for NFC targets, passing the desired NFC
88protocols through NFC_ATTR_PROTOCOLS attribute. The device remains in polling
89state until it finds any target. However, the user can stop the polling
90operation by calling STOP_POLL command. In this case, it will be checked if
91the requester of STOP_POLL is the same of START_POLL.
92
93If the polling operation finds one or more targets, the event TARGETS_FOUND is
94sent (including the device id). The user must call GET_TARGET to get the list of
95all targets found by such device. Each reply message has target attributes with
96relevant information such as the supported NFC protocols.
97
98All polling operations requested through one netlink socket are stopped when
99it's closed.
100
101LOW-LEVEL DATA EXCHANGE:
102
103The userspace must use PF_NFC sockets to perform any data communication with
104targets. All NFC sockets use AF_NFC:
105
106struct sockaddr_nfc {
107 sa_family_t sa_family;
108 __u32 dev_idx;
109 __u32 target_idx;
110 __u32 nfc_protocol;
111};
112
113To establish a connection with one target, the user must create an
114NFC_SOCKPROTO_RAW socket and call the 'connect' syscall with the sockaddr_nfc
115struct correctly filled. All information comes from NFC_EVENT_TARGETS_FOUND
116netlink event. As a target can support more than one NFC protocol, the user
117must inform which protocol it wants to use.
118
119Internally, 'connect' will result in an activate_target call to the driver.
120When the socket is closed, the target is deactivated.
121
122The data format exchanged through the sockets is NFC protocol dependent. For
123instance, when communicating with MIFARE tags, the data exchanged are MIFARE
124commands and their responses.
125
126The first received package is the response to the first sent package and so
127on. In order to allow valid "empty" responses, every data received has a NULL
128header of 1 byte.
diff --git a/Documentation/networking/scaling.txt b/Documentation/networking/scaling.txt
new file mode 100644
index 00000000000..fe67b5c79f0
--- /dev/null
+++ b/Documentation/networking/scaling.txt
@@ -0,0 +1,378 @@
1Scaling in the Linux Networking Stack
2
3
4Introduction
5============
6
7This document describes a set of complementary techniques in the Linux
8networking stack to increase parallelism and improve performance for
9multi-processor systems.
10
11The following technologies are described:
12
13 RSS: Receive Side Scaling
14 RPS: Receive Packet Steering
15 RFS: Receive Flow Steering
16 Accelerated Receive Flow Steering
17 XPS: Transmit Packet Steering
18
19
20RSS: Receive Side Scaling
21=========================
22
23Contemporary NICs support multiple receive and transmit descriptor queues
24(multi-queue). On reception, a NIC can send different packets to different
25queues to distribute processing among CPUs. The NIC distributes packets by
26applying a filter to each packet that assigns it to one of a small number
27of logical flows. Packets for each flow are steered to a separate receive
28queue, which in turn can be processed by separate CPUs. This mechanism is
29generally known as “Receive-side Scaling” (RSS). The goal of RSS and
30the other scaling techniques is to increase performance uniformly.
31Multi-queue distribution can also be used for traffic prioritization, but
32that is not the focus of these techniques.
33
34The filter used in RSS is typically a hash function over the network
35and/or transport layer headers-- for example, a 4-tuple hash over
36IP addresses and TCP ports of a packet. The most common hardware
37implementation of RSS uses a 128-entry indirection table where each entry
38stores a queue number. The receive queue for a packet is determined
39by masking out the low order seven bits of the computed hash for the
40packet (usually a Toeplitz hash), taking this number as a key into the
41indirection table and reading the corresponding value.
42
43Some advanced NICs allow steering packets to queues based on
44programmable filters. For example, webserver bound TCP port 80 packets
45can be directed to their own receive queue. Such “n-tuple” filters can
46be configured from ethtool (--config-ntuple).
47
48==== RSS Configuration
49
50The driver for a multi-queue capable NIC typically provides a kernel
51module parameter for specifying the number of hardware queues to
52configure. In the bnx2x driver, for instance, this parameter is called
53num_queues. A typical RSS configuration would be to have one receive queue
54for each CPU if the device supports enough queues, or otherwise at least
55one for each memory domain, where a memory domain is a set of CPUs that
56share a particular memory level (L1, L2, NUMA node, etc.).
57
58The indirection table of an RSS device, which resolves a queue by masked
59hash, is usually programmed by the driver at initialization. The
60default mapping is to distribute the queues evenly in the table, but the
61indirection table can be retrieved and modified at runtime using ethtool
62commands (--show-rxfh-indir and --set-rxfh-indir). Modifying the
63indirection table could be done to give different queues different
64relative weights.
65
66== RSS IRQ Configuration
67
68Each receive queue has a separate IRQ associated with it. The NIC triggers
69this to notify a CPU when new packets arrive on the given queue. The
70signaling path for PCIe devices uses message signaled interrupts (MSI-X),
71that can route each interrupt to a particular CPU. The active mapping
72of queues to IRQs can be determined from /proc/interrupts. By default,
73an IRQ may be handled on any CPU. Because a non-negligible part of packet
74processing takes place in receive interrupt handling, it is advantageous
75to spread receive interrupts between CPUs. To manually adjust the IRQ
76affinity of each interrupt see Documentation/IRQ-affinity. Some systems
77will be running irqbalance, a daemon that dynamically optimizes IRQ
78assignments and as a result may override any manual settings.
79
80== Suggested Configuration
81
82RSS should be enabled when latency is a concern or whenever receive
83interrupt processing forms a bottleneck. Spreading load between CPUs
84decreases queue length. For low latency networking, the optimal setting
85is to allocate as many queues as there are CPUs in the system (or the
86NIC maximum, if lower). The most efficient high-rate configuration
87is likely the one with the smallest number of receive queues where no
88receive queue overflows due to a saturated CPU, because in default
89mode with interrupt coalescing enabled, the aggregate number of
90interrupts (and thus work) grows with each additional queue.
91
92Per-cpu load can be observed using the mpstat utility, but note that on
93processors with hyperthreading (HT), each hyperthread is represented as
94a separate CPU. For interrupt handling, HT has shown no benefit in
95initial tests, so limit the number of queues to the number of CPU cores
96in the system.
97
98
99RPS: Receive Packet Steering
100============================
101
102Receive Packet Steering (RPS) is logically a software implementation of
103RSS. Being in software, it is necessarily called later in the datapath.
104Whereas RSS selects the queue and hence CPU that will run the hardware
105interrupt handler, RPS selects the CPU to perform protocol processing
106above the interrupt handler. This is accomplished by placing the packet
107on the desired CPU’s backlog queue and waking up the CPU for processing.
108RPS has some advantages over RSS: 1) it can be used with any NIC,
1092) software filters can easily be added to hash over new protocols,
1103) it does not increase hardware device interrupt rate (although it does
111introduce inter-processor interrupts (IPIs)).
112
113RPS is called during bottom half of the receive interrupt handler, when
114a driver sends a packet up the network stack with netif_rx() or
115netif_receive_skb(). These call the get_rps_cpu() function, which
116selects the queue that should process a packet.
117
118The first step in determining the target CPU for RPS is to calculate a
119flow hash over the packet’s addresses or ports (2-tuple or 4-tuple hash
120depending on the protocol). This serves as a consistent hash of the
121associated flow of the packet. The hash is either provided by hardware
122or will be computed in the stack. Capable hardware can pass the hash in
123the receive descriptor for the packet; this would usually be the same
124hash used for RSS (e.g. computed Toeplitz hash). The hash is saved in
125skb->rx_hash and can be used elsewhere in the stack as a hash of the
126packet’s flow.
127
128Each receive hardware queue has an associated list of CPUs to which
129RPS may enqueue packets for processing. For each received packet,
130an index into the list is computed from the flow hash modulo the size
131of the list. The indexed CPU is the target for processing the packet,
132and the packet is queued to the tail of that CPU’s backlog queue. At
133the end of the bottom half routine, IPIs are sent to any CPUs for which
134packets have been queued to their backlog queue. The IPI wakes backlog
135processing on the remote CPU, and any queued packets are then processed
136up the networking stack.
137
138==== RPS Configuration
139
140RPS requires a kernel compiled with the CONFIG_RPS kconfig symbol (on
141by default for SMP). Even when compiled in, RPS remains disabled until
142explicitly configured. The list of CPUs to which RPS may forward traffic
143can be configured for each receive queue using a sysfs file entry:
144
145 /sys/class/net/<dev>/queues/rx-<n>/rps_cpus
146
147This file implements a bitmap of CPUs. RPS is disabled when it is zero
148(the default), in which case packets are processed on the interrupting
149CPU. Documentation/IRQ-affinity.txt explains how CPUs are assigned to
150the bitmap.
151
152== Suggested Configuration
153
154For a single queue device, a typical RPS configuration would be to set
155the rps_cpus to the CPUs in the same memory domain of the interrupting
156CPU. If NUMA locality is not an issue, this could also be all CPUs in
157the system. At high interrupt rate, it might be wise to exclude the
158interrupting CPU from the map since that already performs much work.
159
160For a multi-queue system, if RSS is configured so that a hardware
161receive queue is mapped to each CPU, then RPS is probably redundant
162and unnecessary. If there are fewer hardware queues than CPUs, then
163RPS might be beneficial if the rps_cpus for each queue are the ones that
164share the same memory domain as the interrupting CPU for that queue.
165
166
167RFS: Receive Flow Steering
168==========================
169
170While RPS steers packets solely based on hash, and thus generally
171provides good load distribution, it does not take into account
172application locality. This is accomplished by Receive Flow Steering
173(RFS). The goal of RFS is to increase datacache hitrate by steering
174kernel processing of packets to the CPU where the application thread
175consuming the packet is running. RFS relies on the same RPS mechanisms
176to enqueue packets onto the backlog of another CPU and to wake up that
177CPU.
178
179In RFS, packets are not forwarded directly by the value of their hash,
180but the hash is used as index into a flow lookup table. This table maps
181flows to the CPUs where those flows are being processed. The flow hash
182(see RPS section above) is used to calculate the index into this table.
183The CPU recorded in each entry is the one which last processed the flow.
184If an entry does not hold a valid CPU, then packets mapped to that entry
185are steered using plain RPS. Multiple table entries may point to the
186same CPU. Indeed, with many flows and few CPUs, it is very likely that
187a single application thread handles flows with many different flow hashes.
188
189rps_sock_flow_table is a global flow table that contains the *desired* CPU
190for flows: the CPU that is currently processing the flow in userspace.
191Each table value is a CPU index that is updated during calls to recvmsg
192and sendmsg (specifically, inet_recvmsg(), inet_sendmsg(), inet_sendpage()
193and tcp_splice_read()).
194
195When the scheduler moves a thread to a new CPU while it has outstanding
196receive packets on the old CPU, packets may arrive out of order. To
197avoid this, RFS uses a second flow table to track outstanding packets
198for each flow: rps_dev_flow_table is a table specific to each hardware
199receive queue of each device. Each table value stores a CPU index and a
200counter. The CPU index represents the *current* CPU onto which packets
201for this flow are enqueued for further kernel processing. Ideally, kernel
202and userspace processing occur on the same CPU, and hence the CPU index
203in both tables is identical. This is likely false if the scheduler has
204recently migrated a userspace thread while the kernel still has packets
205enqueued for kernel processing on the old CPU.
206
207The counter in rps_dev_flow_table values records the length of the current
208CPU's backlog when a packet in this flow was last enqueued. Each backlog
209queue has a head counter that is incremented on dequeue. A tail counter
210is computed as head counter + queue length. In other words, the counter
211in rps_dev_flow_table[i] records the last element in flow i that has
212been enqueued onto the currently designated CPU for flow i (of course,
213entry i is actually selected by hash and multiple flows may hash to the
214same entry i).
215
216And now the trick for avoiding out of order packets: when selecting the
217CPU for packet processing (from get_rps_cpu()) the rps_sock_flow table
218and the rps_dev_flow table of the queue that the packet was received on
219are compared. If the desired CPU for the flow (found in the
220rps_sock_flow table) matches the current CPU (found in the rps_dev_flow
221table), the packet is enqueued onto that CPU’s backlog. If they differ,
222the current CPU is updated to match the desired CPU if one of the
223following is true:
224
225- The current CPU's queue head counter >= the recorded tail counter
226 value in rps_dev_flow[i]
227- The current CPU is unset (equal to NR_CPUS)
228- The current CPU is offline
229
230After this check, the packet is sent to the (possibly updated) current
231CPU. These rules aim to ensure that a flow only moves to a new CPU when
232there are no packets outstanding on the old CPU, as the outstanding
233packets could arrive later than those about to be processed on the new
234CPU.
235
236==== RFS Configuration
237
238RFS is only available if the kconfig symbol CONFIG_RFS is enabled (on
239by default for SMP). The functionality remains disabled until explicitly
240configured. The number of entries in the global flow table is set through:
241
242 /proc/sys/net/core/rps_sock_flow_entries
243
244The number of entries in the per-queue flow table are set through:
245
246 /sys/class/net/<dev>/queues/rx-<n>/rps_flow_cnt
247
248== Suggested Configuration
249
250Both of these need to be set before RFS is enabled for a receive queue.
251Values for both are rounded up to the nearest power of two. The
252suggested flow count depends on the expected number of active connections
253at any given time, which may be significantly less than the number of open
254connections. We have found that a value of 32768 for rps_sock_flow_entries
255works fairly well on a moderately loaded server.
256
257For a single queue device, the rps_flow_cnt value for the single queue
258would normally be configured to the same value as rps_sock_flow_entries.
259For a multi-queue device, the rps_flow_cnt for each queue might be
260configured as rps_sock_flow_entries / N, where N is the number of
261queues. So for instance, if rps_flow_entries is set to 32768 and there
262are 16 configured receive queues, rps_flow_cnt for each queue might be
263configured as 2048.
264
265
266Accelerated RFS
267===============
268
269Accelerated RFS is to RFS what RSS is to RPS: a hardware-accelerated load
270balancing mechanism that uses soft state to steer flows based on where
271the application thread consuming the packets of each flow is running.
272Accelerated RFS should perform better than RFS since packets are sent
273directly to a CPU local to the thread consuming the data. The target CPU
274will either be the same CPU where the application runs, or at least a CPU
275which is local to the application thread’s CPU in the cache hierarchy.
276
277To enable accelerated RFS, the networking stack calls the
278ndo_rx_flow_steer driver function to communicate the desired hardware
279queue for packets matching a particular flow. The network stack
280automatically calls this function every time a flow entry in
281rps_dev_flow_table is updated. The driver in turn uses a device specific
282method to program the NIC to steer the packets.
283
284The hardware queue for a flow is derived from the CPU recorded in
285rps_dev_flow_table. The stack consults a CPU to hardware queue map which
286is maintained by the NIC driver. This is an auto-generated reverse map of
287the IRQ affinity table shown by /proc/interrupts. Drivers can use
288functions in the cpu_rmap (“CPU affinity reverse map”) kernel library
289to populate the map. For each CPU, the corresponding queue in the map is
290set to be one whose processing CPU is closest in cache locality.
291
292==== Accelerated RFS Configuration
293
294Accelerated RFS is only available if the kernel is compiled with
295CONFIG_RFS_ACCEL and support is provided by the NIC device and driver.
296It also requires that ntuple filtering is enabled via ethtool. The map
297of CPU to queues is automatically deduced from the IRQ affinities
298configured for each receive queue by the driver, so no additional
299configuration should be necessary.
300
301== Suggested Configuration
302
303This technique should be enabled whenever one wants to use RFS and the
304NIC supports hardware acceleration.
305
306XPS: Transmit Packet Steering
307=============================
308
309Transmit Packet Steering is a mechanism for intelligently selecting
310which transmit queue to use when transmitting a packet on a multi-queue
311device. To accomplish this, a mapping from CPU to hardware queue(s) is
312recorded. The goal of this mapping is usually to assign queues
313exclusively to a subset of CPUs, where the transmit completions for
314these queues are processed on a CPU within this set. This choice
315provides two benefits. First, contention on the device queue lock is
316significantly reduced since fewer CPUs contend for the same queue
317(contention can be eliminated completely if each CPU has its own
318transmit queue). Secondly, cache miss rate on transmit completion is
319reduced, in particular for data cache lines that hold the sk_buff
320structures.
321
322XPS is configured per transmit queue by setting a bitmap of CPUs that
323may use that queue to transmit. The reverse mapping, from CPUs to
324transmit queues, is computed and maintained for each network device.
325When transmitting the first packet in a flow, the function
326get_xps_queue() is called to select a queue. This function uses the ID
327of the running CPU as a key into the CPU-to-queue lookup table. If the
328ID matches a single queue, that is used for transmission. If multiple
329queues match, one is selected by using the flow hash to compute an index
330into the set.
331
332The queue chosen for transmitting a particular flow is saved in the
333corresponding socket structure for the flow (e.g. a TCP connection).
334This transmit queue is used for subsequent packets sent on the flow to
335prevent out of order (ooo) packets. The choice also amortizes the cost
336of calling get_xps_queues() over all packets in the flow. To avoid
337ooo packets, the queue for a flow can subsequently only be changed if
338skb->ooo_okay is set for a packet in the flow. This flag indicates that
339there are no outstanding packets in the flow, so the transmit queue can
340change without the risk of generating out of order packets. The
341transport layer is responsible for setting ooo_okay appropriately. TCP,
342for instance, sets the flag when all data for a connection has been
343acknowledged.
344
345==== XPS Configuration
346
347XPS is only available if the kconfig symbol CONFIG_XPS is enabled (on by
348default for SMP). The functionality remains disabled until explicitly
349configured. To enable XPS, the bitmap of CPUs that may use a transmit
350queue is configured using the sysfs file entry:
351
352/sys/class/net/<dev>/queues/tx-<n>/xps_cpus
353
354== Suggested Configuration
355
356For a network device with a single transmission queue, XPS configuration
357has no effect, since there is no choice in this case. In a multi-queue
358system, XPS is preferably configured so that each CPU maps onto one queue.
359If there are as many queues as there are CPUs in the system, then each
360queue can also map onto one CPU, resulting in exclusive pairings that
361experience no contention. If there are fewer queues than CPUs, then the
362best CPUs to share a given queue are probably those that share the cache
363with the CPU that processes transmit completions for that queue
364(transmit interrupts).
365
366
367Further Information
368===================
369RPS and RFS were introduced in kernel 2.6.35. XPS was incorporated into
3702.6.38. Original patches were submitted by Tom Herbert
371(therbert@google.com)
372
373Accelerated RFS was introduced in 2.6.35. Original patches were
374submitted by Ben Hutchings (bhutchings@solarflare.com)
375
376Authors:
377Tom Herbert (therbert@google.com)
378Willem de Bruijn (willemb@google.com)
diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/stmmac.txt
index 80a7a345490..57a24108b84 100644
--- a/Documentation/networking/stmmac.txt
+++ b/Documentation/networking/stmmac.txt
@@ -7,7 +7,7 @@ This is the driver for the MAC 10/100/1000 on-chip Ethernet controllers
7(Synopsys IP blocks); it has been fully tested on STLinux platforms. 7(Synopsys IP blocks); it has been fully tested on STLinux platforms.
8 8
9Currently this network device driver is for all STM embedded MAC/GMAC 9Currently this network device driver is for all STM embedded MAC/GMAC
10(7xxx SoCs). Other platforms start using it i.e. ARM SPEAr. 10(i.e. 7xxx/5xxx SoCs) and it's known working on other platforms i.e. ARM SPEAr.
11 11
12DWC Ether MAC 10/100/1000 Universal version 3.41a and DWC Ether MAC 10/100 12DWC Ether MAC 10/100/1000 Universal version 3.41a and DWC Ether MAC 10/100
13Universal version 4.0 have been used for developing the first code 13Universal version 4.0 have been used for developing the first code
@@ -71,7 +71,7 @@ Several performance tests on STM platforms showed this optimisation allows to sp
71the CPU while having the maximum throughput. 71the CPU while having the maximum throughput.
72 72
734.4) WOL 734.4) WOL
74Wake up on Lan feature through Magic Frame is only supported for the GMAC 74Wake up on Lan feature through Magic and Unicast frames are supported for the GMAC
75core. 75core.
76 76
774.5) DMA descriptors 774.5) DMA descriptors
@@ -91,11 +91,15 @@ LRO is not supported.
91The driver is compatible with PAL to work with PHY and GPHY devices. 91The driver is compatible with PAL to work with PHY and GPHY devices.
92 92
934.9) Platform information 934.9) Platform information
94Several information came from the platform; please refer to the 94Several driver's information can be passed through the platform
95driver's Header file in include/linux directory. 95These are included in the include/linux/stmmac.h header file
96and detailed below as well:
96 97
97struct plat_stmmacenet_data { 98 struct plat_stmmacenet_data {
98 int bus_id; 99 int bus_id;
100 int phy_addr;
101 int interface;
102 struct stmmac_mdio_bus_data *mdio_bus_data;
99 int pbl; 103 int pbl;
100 int clk_csr; 104 int clk_csr;
101 int has_gmac; 105 int has_gmac;
@@ -103,67 +107,135 @@ struct plat_stmmacenet_data {
103 int tx_coe; 107 int tx_coe;
104 int bugged_jumbo; 108 int bugged_jumbo;
105 int pmt; 109 int pmt;
106 void (*fix_mac_speed)(void *priv, unsigned int speed); 110 int force_sf_dma_mode;
107 void (*bus_setup)(unsigned long ioaddr); 111 void (*fix_mac_speed)(void *priv, unsigned int speed);
108#ifdef CONFIG_STM_DRIVERS 112 void (*bus_setup)(void __iomem *ioaddr);
109 struct stm_pad_config *pad_config; 113 int (*init)(struct platform_device *pdev);
110#endif 114 void (*exit)(struct platform_device *pdev);
111 void *bsp_priv; 115 void *bsp_priv;
112}; 116 };
113 117
114Where: 118Where:
115- pbl (Programmable Burst Length) is maximum number of 119 o bus_id: bus identifier.
116 beats to be transferred in one DMA transaction. 120 o phy_addr: the physical address can be passed from the platform.
117 GMAC also enables the 4xPBL by default. 121 If it is set to -1 the driver will automatically
118- fix_mac_speed and bus_setup are used to configure internal target 122 detect it at run-time by probing all the 32 addresses.
119 registers (on STM platforms); 123 o interface: PHY device's interface.
120- has_gmac: GMAC core is on board (get it at run-time in the next step); 124 o mdio_bus_data: specific platform fields for the MDIO bus.
121- bus_id: bus identifier. 125 o pbl: the Programmable Burst Length is maximum number of beats to
122- tx_coe: core is able to perform the tx csum in HW. 126 be transferred in one DMA transaction.
123- enh_desc: if sets the MAC will use the enhanced descriptor structure. 127 GMAC also enables the 4xPBL by default.
124- clk_csr: CSR Clock range selection. 128 o clk_csr: CSR Clock range selection.
125- bugged_jumbo: some HWs are not able to perform the csum in HW for 129 o has_gmac: uses the GMAC core.
126 over-sized frames due to limited buffer sizes. Setting this 130 o enh_desc: if sets the MAC will use the enhanced descriptor structure.
127 flag the csum will be done in SW on JUMBO frames. 131 o tx_coe: core is able to perform the tx csum in HW.
128 132 o bugged_jumbo: some HWs are not able to perform the csum in HW for
129struct plat_stmmacphy_data { 133 over-sized frames due to limited buffer sizes.
130 int bus_id; 134 Setting this flag the csum will be done in SW on
131 int phy_addr; 135 JUMBO frames.
132 unsigned int phy_mask; 136 o pmt: core has the embedded power module (optional).
133 int interface; 137 o force_sf_dma_mode: force DMA to use the Store and Forward mode
134 int (*phy_reset)(void *priv); 138 instead of the Threshold.
135 void *priv; 139 o fix_mac_speed: this callback is used for modifying some syscfg registers
136}; 140 (on ST SoCs) according to the link speed negotiated by the
141 physical layer .
142 o bus_setup: perform HW setup of the bus. For example, on some ST platforms
143 this field is used to configure the AMBA bridge to generate more
144 efficient STBus traffic.
145 o init/exit: callbacks used for calling a custom initialisation;
146 this is sometime necessary on some platforms (e.g. ST boxes)
147 where the HW needs to have set some PIO lines or system cfg
148 registers.
149 o custom_cfg: this is a custom configuration that can be passed while
150 initialising the resources.
151
152The we have:
153
154 struct stmmac_mdio_bus_data {
155 int bus_id;
156 int (*phy_reset)(void *priv);
157 unsigned int phy_mask;
158 int *irqs;
159 int probed_phy_irq;
160 };
137 161
138Where: 162Where:
139- bus_id: bus identifier; 163 o bus_id: bus identifier;
140- phy_addr: physical address used for the attached phy device; 164 o phy_reset: hook to reset the phy device attached to the bus.
141 set it to -1 to get it at run-time; 165 o phy_mask: phy mask passed when register the MDIO bus within the driver.
142- interface: physical MII interface mode; 166 o irqs: list of IRQs, one per PHY.
143- phy_reset: hook to reset HW function. 167 o probed_phy_irq: if irqs is NULL, use this for probed PHY.
144 168
145SOURCES: 169Below an example how the structures above are using on ST platforms.
146- Kconfig 170
147- Makefile 171 static struct plat_stmmacenet_data stxYYY_ethernet_platform_data = {
148- stmmac_main.c: main network device driver; 172 .pbl = 32,
149- stmmac_mdio.c: mdio functions; 173 .has_gmac = 0,
150- stmmac_ethtool.c: ethtool support; 174 .enh_desc = 0,
151- stmmac_timer.[ch]: timer code used for mitigating the driver dma interrupts 175 .fix_mac_speed = stxYYY_ethernet_fix_mac_speed,
152 Only tested on ST40 platforms based. 176 |
153- stmmac.h: private driver structure; 177 |-> to write an internal syscfg
154- common.h: common definitions and VFTs; 178 | on this platform when the
155- descs.h: descriptor structure definitions; 179 | link speed changes from 10 to
156- dwmac1000_core.c: GMAC core functions; 180 | 100 and viceversa
157- dwmac1000_dma.c: dma functions for the GMAC chip; 181 .init = &stmmac_claim_resource,
158- dwmac1000.h: specific header file for the GMAC; 182 |
159- dwmac100_core: MAC 100 core and dma code; 183 |-> On ST SoC this calls own "PAD"
160- dwmac100_dma.c: dma funtions for the MAC chip; 184 | manager framework to claim
161- dwmac1000.h: specific header file for the MAC; 185 | all the resources necessary
162- dwmac_lib.c: generic DMA functions shared among chips 186 | (GPIO ...). The .custom_cfg field
163- enh_desc.c: functions for handling enhanced descriptors 187 | is used to pass a custom config.
164- norm_desc.c: functions for handling normal descriptors 188};
165 189
166TODO: 190Below the usage of the stmmac_mdio_bus_data: on this SoC, in fact,
167- XGMAC controller is not supported. 191there are two MAC cores: one MAC is for MDIO Bus/PHY emulation
168- Review the timer optimisation code to use an embedded device that seems to be 192with fixed_link support.
193
194static struct stmmac_mdio_bus_data stmmac1_mdio_bus = {
195 .bus_id = 1,
196 |
197 |-> phy device on the bus_id 1
198 .phy_reset = phy_reset;
199 |
200 |-> function to provide the phy_reset on this board
201 .phy_mask = 0,
202};
203
204static struct fixed_phy_status stmmac0_fixed_phy_status = {
205 .link = 1,
206 .speed = 100,
207 .duplex = 1,
208};
209
210During the board's device_init we can configure the first
211MAC for fixed_link by calling:
212 fixed_phy_add(PHY_POLL, 1, &stmmac0_fixed_phy_status));)
213and the second one, with a real PHY device attached to the bus,
214by using the stmmac_mdio_bus_data structure (to provide the id, the
215reset procedure etc).
216
2174.10) List of source files:
218 o Kconfig
219 o Makefile
220 o stmmac_main.c: main network device driver;
221 o stmmac_mdio.c: mdio functions;
222 o stmmac_ethtool.c: ethtool support;
223 o stmmac_timer.[ch]: timer code used for mitigating the driver dma interrupts
224 Only tested on ST40 platforms based.
225 o stmmac.h: private driver structure;
226 o common.h: common definitions and VFTs;
227 o descs.h: descriptor structure definitions;
228 o dwmac1000_core.c: GMAC core functions;
229 o dwmac1000_dma.c: dma functions for the GMAC chip;
230 o dwmac1000.h: specific header file for the GMAC;
231 o dwmac100_core: MAC 100 core and dma code;
232 o dwmac100_dma.c: dma funtions for the MAC chip;
233 o dwmac1000.h: specific header file for the MAC;
234 o dwmac_lib.c: generic DMA functions shared among chips
235 o enh_desc.c: functions for handling enhanced descriptors
236 o norm_desc.c: functions for handling normal descriptors
237
2385) TODO:
239 o XGMAC is not supported.
240 o Review the timer optimisation code to use an embedded device that will be
169 available in new chip generations. 241 available in new chip generations.