diff options
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/cgroups/cpuacct.txt | 18 | ||||
-rw-r--r-- | Documentation/feature-removal-schedule.txt | 9 | ||||
-rw-r--r-- | Documentation/infiniband/ipoib.txt | 45 | ||||
-rw-r--r-- | Documentation/trace/ftrace.txt (renamed from Documentation/ftrace.txt) | 0 | ||||
-rw-r--r-- | Documentation/trace/kmemtrace.txt (renamed from Documentation/vm/kmemtrace.txt) | 0 | ||||
-rw-r--r-- | Documentation/trace/mmiotrace.txt (renamed from Documentation/tracers/mmiotrace.txt) | 0 | ||||
-rw-r--r-- | Documentation/trace/tracepoints.txt (renamed from Documentation/tracepoints.txt) | 0 |
7 files changed, 72 insertions, 0 deletions
diff --git a/Documentation/cgroups/cpuacct.txt b/Documentation/cgroups/cpuacct.txt index bb775fbe43d7..8b930946c52a 100644 --- a/Documentation/cgroups/cpuacct.txt +++ b/Documentation/cgroups/cpuacct.txt | |||
@@ -30,3 +30,21 @@ The above steps create a new group g1 and move the current shell | |||
30 | process (bash) into it. CPU time consumed by this bash and its children | 30 | process (bash) into it. CPU time consumed by this bash and its children |
31 | can be obtained from g1/cpuacct.usage and the same is accumulated in | 31 | can be obtained from g1/cpuacct.usage and the same is accumulated in |
32 | /cgroups/cpuacct.usage also. | 32 | /cgroups/cpuacct.usage also. |
33 | |||
34 | cpuacct.stat file lists a few statistics which further divide the | ||
35 | CPU time obtained by the cgroup into user and system times. Currently | ||
36 | the following statistics are supported: | ||
37 | |||
38 | user: Time spent by tasks of the cgroup in user mode. | ||
39 | system: Time spent by tasks of the cgroup in kernel mode. | ||
40 | |||
41 | user and system are in USER_HZ unit. | ||
42 | |||
43 | cpuacct controller uses percpu_counter interface to collect user and | ||
44 | system times. This has two side effects: | ||
45 | |||
46 | - It is theoretically possible to see wrong values for user and system times. | ||
47 | This is because percpu_counter_read() on 32bit systems isn't safe | ||
48 | against concurrent writes. | ||
49 | - It is possible to see slightly outdated values for user and system times | ||
50 | due to the batch processing nature of percpu_counter. | ||
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 7e2af10e8264..de491a3e2313 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt | |||
@@ -428,3 +428,12 @@ Why: In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to | |||
428 | After a reasonable transition period, we will remove the legacy | 428 | After a reasonable transition period, we will remove the legacy |
429 | fakephp interface. | 429 | fakephp interface. |
430 | Who: Alex Chiang <achiang@hp.com> | 430 | Who: Alex Chiang <achiang@hp.com> |
431 | |||
432 | --------------------------- | ||
433 | |||
434 | What: i2c-voodoo3 driver | ||
435 | When: October 2009 | ||
436 | Why: Superseded by tdfxfb. I2C/DDC support used to live in a separate | ||
437 | driver but this caused driver conflicts. | ||
438 | Who: Jean Delvare <khali@linux-fr.org> | ||
439 | Krzysztof Helt <krzysztof.h1@wp.pl> | ||
diff --git a/Documentation/infiniband/ipoib.txt b/Documentation/infiniband/ipoib.txt index 864ff3283780..6d40f00b358c 100644 --- a/Documentation/infiniband/ipoib.txt +++ b/Documentation/infiniband/ipoib.txt | |||
@@ -24,6 +24,49 @@ Partitions and P_Keys | |||
24 | The P_Key for any interface is given by the "pkey" file, and the | 24 | The P_Key for any interface is given by the "pkey" file, and the |
25 | main interface for a subinterface is in "parent." | 25 | main interface for a subinterface is in "parent." |
26 | 26 | ||
27 | Datagram vs Connected modes | ||
28 | |||
29 | The IPoIB driver supports two modes of operation: datagram and | ||
30 | connected. The mode is set and read through an interface's | ||
31 | /sys/class/net/<intf name>/mode file. | ||
32 | |||
33 | In datagram mode, the IB UD (Unreliable Datagram) transport is used | ||
34 | and so the interface MTU has is equal to the IB L2 MTU minus the | ||
35 | IPoIB encapsulation header (4 bytes). For example, in a typical IB | ||
36 | fabric with a 2K MTU, the IPoIB MTU will be 2048 - 4 = 2044 bytes. | ||
37 | |||
38 | In connected mode, the IB RC (Reliable Connected) transport is used. | ||
39 | Connected mode is to takes advantage of the connected nature of the | ||
40 | IB transport and allows an MTU up to the maximal IP packet size of | ||
41 | 64K, which reduces the number of IP packets needed for handling | ||
42 | large UDP datagrams, TCP segments, etc and increases the performance | ||
43 | for large messages. | ||
44 | |||
45 | In connected mode, the interface's UD QP is still used for multicast | ||
46 | and communication with peers that don't support connected mode. In | ||
47 | this case, RX emulation of ICMP PMTU packets is used to cause the | ||
48 | networking stack to use the smaller UD MTU for these neighbours. | ||
49 | |||
50 | Stateless offloads | ||
51 | |||
52 | If the IB HW supports IPoIB stateless offloads, IPoIB advertises | ||
53 | TCP/IP checksum and/or Large Send (LSO) offloading capability to the | ||
54 | network stack. | ||
55 | |||
56 | Large Receive (LRO) offloading is also implemented and may be turned | ||
57 | on/off using ethtool calls. Currently LRO is supported only for | ||
58 | checksum offload capable devices. | ||
59 | |||
60 | Stateless offloads are supported only in datagram mode. | ||
61 | |||
62 | Interrupt moderation | ||
63 | |||
64 | If the underlying IB device supports CQ event moderation, one can | ||
65 | use ethtool to set interrupt mitigation parameters and thus reduce | ||
66 | the overhead incurred by handling interrupts. The main code path of | ||
67 | IPoIB doesn't use events for TX completion signaling so only RX | ||
68 | moderation is supported. | ||
69 | |||
27 | Debugging Information | 70 | Debugging Information |
28 | 71 | ||
29 | By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set | 72 | By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set |
@@ -55,3 +98,5 @@ References | |||
55 | http://ietf.org/rfc/rfc4391.txt | 98 | http://ietf.org/rfc/rfc4391.txt |
56 | IP over InfiniBand (IPoIB) Architecture (RFC 4392) | 99 | IP over InfiniBand (IPoIB) Architecture (RFC 4392) |
57 | http://ietf.org/rfc/rfc4392.txt | 100 | http://ietf.org/rfc/rfc4392.txt |
101 | IP over InfiniBand: Connected Mode (RFC 4755) | ||
102 | http://ietf.org/rfc/rfc4755.txt | ||
diff --git a/Documentation/ftrace.txt b/Documentation/trace/ftrace.txt index fd9a3e693813..fd9a3e693813 100644 --- a/Documentation/ftrace.txt +++ b/Documentation/trace/ftrace.txt | |||
diff --git a/Documentation/vm/kmemtrace.txt b/Documentation/trace/kmemtrace.txt index a956d9b7f943..a956d9b7f943 100644 --- a/Documentation/vm/kmemtrace.txt +++ b/Documentation/trace/kmemtrace.txt | |||
diff --git a/Documentation/tracers/mmiotrace.txt b/Documentation/trace/mmiotrace.txt index 5731c67abc55..5731c67abc55 100644 --- a/Documentation/tracers/mmiotrace.txt +++ b/Documentation/trace/mmiotrace.txt | |||
diff --git a/Documentation/tracepoints.txt b/Documentation/trace/tracepoints.txt index c0e1ceed75a4..c0e1ceed75a4 100644 --- a/Documentation/tracepoints.txt +++ b/Documentation/trace/tracepoints.txt | |||