From df13cce53a7b28a81460e6bfc4857e9df4956141 Mon Sep 17 00:00:00 2001 From: Helmut Schaa Date: Wed, 24 Feb 2010 14:19:21 +0100 Subject: mac80211: Improve software scan timing The current software scan implemenation in mac80211 returns to the operating channel after each scanned channel. However, in some situations (e.g. no traffic) it would be nicer to scan a few channels in a row to speed up the scan itself. Hence, after scanning a channel, check if we have queued up any tx frames and return to the operating channel in that case. Unfortunately we don't know if the AP has buffered any frames for us. Hence, scan only as many channels in a row as the pm_qos latency and the negotiated listen interval allows us to. Signed-off-by: Helmut Schaa Signed-off-by: John W. Linville --- net/mac80211/scan.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 65 insertions(+), 6 deletions(-) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index b822dce97867..75a85978c3b3 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -14,6 +14,8 @@ #include #include +#include +#include #include #include "ieee80211_i.h" @@ -321,6 +323,7 @@ static int ieee80211_start_sw_scan(struct ieee80211_local *local) ieee80211_offchannel_stop_beaconing(local); + local->leave_oper_channel_time = 0; local->next_scan_state = SCAN_DECISION; local->scan_channel_idx = 0; @@ -425,11 +428,28 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, return rc; } +static unsigned long +ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) +{ + /* + * TODO: channel switching also consumes quite some time, + * add that delay as well to get a better estimation + */ + if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) + return IEEE80211_PASSIVE_CHANNEL_TIME; + return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; +} + static int ieee80211_scan_state_decision(struct ieee80211_local *local, unsigned long *next_delay) { bool associated = false; + bool tx_empty = true; + bool bad_latency; + bool listen_int_exceeded; + unsigned long min_beacon_int = 0; struct ieee80211_sub_if_data *sdata; + struct ieee80211_channel *next_chan; /* if no more bands/channels left, complete scan and advance to the idle state */ if (local->scan_channel_idx >= local->scan_req->n_channels) { @@ -437,7 +457,11 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local, return 1; } - /* check if at least one STA interface is associated */ + /* + * check if at least one STA interface is associated, + * check if at least one STA interface has pending tx frames + * and grab the lowest used beacon interval + */ mutex_lock(&local->iflist_mtx); list_for_each_entry(sdata, &local->interfaces, list) { if (!ieee80211_sdata_running(sdata)) @@ -446,7 +470,16 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local, if (sdata->vif.type == NL80211_IFTYPE_STATION) { if (sdata->u.mgd.associated) { associated = true; - break; + + if (sdata->vif.bss_conf.beacon_int < + min_beacon_int || min_beacon_int == 0) + min_beacon_int = + sdata->vif.bss_conf.beacon_int; + + if (!qdisc_all_tx_empty(sdata->dev)) { + tx_empty = false; + break; + } } } } @@ -455,11 +488,34 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local, if (local->scan_channel) { /* * we're currently scanning a different channel, let's - * switch back to the operating channel now if at least - * one interface is associated. Otherwise just scan the - * next channel + * see if we can scan another channel without interfering + * with the current traffic situation. + * + * Since we don't know if the AP has pending frames for us + * we can only check for our tx queues and use the current + * pm_qos requirements for rx. Hence, if no tx traffic occurs + * at all we will scan as many channels in a row as the pm_qos + * latency allows us to. Additionally we also check for the + * currently negotiated listen interval to prevent losing + * frames unnecessarily. + * + * Otherwise switch back to the operating channel. */ - if (associated) + next_chan = local->scan_req->channels[local->scan_channel_idx]; + + bad_latency = time_after(jiffies + + ieee80211_scan_get_channel_time(next_chan), + local->leave_oper_channel_time + + usecs_to_jiffies(pm_qos_requirement(PM_QOS_NETWORK_LATENCY))); + + listen_int_exceeded = time_after(jiffies + + ieee80211_scan_get_channel_time(next_chan), + local->leave_oper_channel_time + + usecs_to_jiffies(min_beacon_int * 1024) * + local->hw.conf.listen_interval); + + if (associated && ( !tx_empty || bad_latency || + listen_int_exceeded)) local->next_scan_state = SCAN_ENTER_OPER_CHANNEL; else local->next_scan_state = SCAN_SET_CHANNEL; @@ -491,6 +547,9 @@ static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *loca else *next_delay = HZ / 10; + /* remember when we left the operating channel */ + local->leave_oper_channel_time = jiffies; + /* advance to the next channel to be scanned */ local->next_scan_state = SCAN_SET_CHANNEL; } -- cgit v1.2.2 From 5a0e3ad6af8660be21ca98a971cd00f331318c05 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 24 Mar 2010 17:04:11 +0900 Subject: include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo Guess-its-ok-by: Christoph Lameter Cc: Ingo Molnar Cc: Lee Schermerhorn --- net/mac80211/scan.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index b822dce97867..85507bd9e341 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -14,6 +14,7 @@ #include #include +#include #include #include "ieee80211_i.h" -- cgit v1.2.2 From b5878a2dc5e7e7f031a52c3e15b571224cb6b540 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 7 Apr 2010 16:48:40 +0200 Subject: mac80211: enhance tracing Enhance tracing by adding tracing for a variety of callbacks that the drivers call, and also for internal calls (currently limited to queue status). This can aid debugging what is going on in mac80211 in interaction with drivers, since we can now see what drivers call and not just what mac80211 calls in the driver. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/scan.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index 75a85978c3b3..eb86a5f6e645 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -247,6 +247,8 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) struct ieee80211_local *local = hw_to_local(hw); bool was_hw_scan; + trace_api_scan_completed(local, aborted); + mutex_lock(&local->scan_mtx); /* -- cgit v1.2.2