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* proc_sched_show_task(): use get_nr_threads()Oleg Nesterov2010-05-27
| | | | | | | | | | | | | | | | | | | | | Trivial, use get_nr_threads() helper to read signal->count which we are going to change. Like other callers, proc_sched_show_task() doesn't need the exactly precise nr_threads. David said: : Note that get_nr_threads() isn't completely equivalent (it can return 0 : where proc_sched_show_task() will display a 1). But I don't think this : should be a problem. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2010-05-18
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (49 commits) stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_callback() sched, wait: Use wrapper functions sched: Remove a stale comment ondemand: Make the iowait-is-busy time a sysfs tunable ondemand: Solve a big performance issue by counting IOWAIT time as busy sched: Intoduce get_cpu_iowait_time_us() sched: Eliminate the ts->idle_lastupdate field sched: Fold updating of the last_update_time_info into update_ts_time_stats() sched: Update the idle statistics in get_cpu_idle_time_us() sched: Introduce a function to update the idle statistics sched: Add a comment to get_cpu_idle_time_us() cpu_stop: add dummy implementation for UP sched: Remove rq argument to the tracepoints rcu: need barrier() in UP synchronize_sched_expedited() sched: correctly place paranioa memory barriers in synchronize_sched_expedited() sched: kill paranoia check in synchronize_sched_expedited() sched: replace migration_thread with cpu_stop stop_machine: reimplement using cpu_stop cpu_stop: implement stop_cpu[s]() sched: Fix select_idle_sibling() logic in select_task_rq_fair() ...
| * Merge branch 'linus' into sched/coreIngo Molnar2010-04-15
| |\ | | | | | | | | | | | | | | | Merge reason: merge the latest fixes, update to -rc4. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Remove remaining USER_SCHED codeLi Zefan2010-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is left over from commit 7c9414385e ("sched: Remove USER_SCHED"") Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Dhaval Giani <dhaval.giani@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: David Howells <dhowells@redhat.com> LKML-Reference: <4BA9A05F.7010407@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Remove avg_overlapMike Galbraith2010-03-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Both avg_overlap and avg_wakeup had an inherent problem in that their accuracy was detrimentally affected by cross-cpu wakeups, this because we are missing the necessary call to update_curr(). This can't be fixed without increasing overhead in our already too fat fastpath. Additionally, with recent load balancing changes making us prefer to place tasks in an idle cache domain (which is good for compute bound loads), communicating tasks suffer when a sync wakeup, which would enable affine placement, is turned into a non-sync wakeup by SYNC_LESS. With one task on the runqueue, wake_affine() rejects the affine wakeup request, leaving the unfortunate where placed, taking frequent cache misses. Remove it, and recover some fastpath cycles. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301121.6785.30.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Remove avg_wakeupMike Galbraith2010-03-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Testing the load which led to this heuristic (nfs4 kbuild) shows that it has outlived it's usefullness. With intervening load balancing changes, I cannot see any difference with/without, so recover there fastpath cycles. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301062.6785.29.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Implement group scheduler statistics in one structLucas De Marchi2010-03-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Put all statistic fields of sched_entity in one struct, sched_statistics, and embed it into sched_entity. This change allows to memset the sched_statistics to 0 when needed (for instance when forking), avoiding bugs of non initialized fields. Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268275065-18542-1-git-send-email-lucas.de.marchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Fix an RCU warning in print_task()Li Zefan2010-05-04
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With CONFIG_PROVE_RCU=y, a warning can be triggered: $ cat /proc/sched_debug ... kernel/cgroup.c:1649 invoked rcu_dereference_check() without protection! ... Both cgroup_path() and task_group() should be called with either rcu_read_lock or cgroup_mutex held. The rcu_dereference_check() does include cgroup_lock_is_held(), so we know that this lock is not held. Therefore, in a CONFIG_PREEMPT kernel, to say nothing of a CONFIG_PREEMPT_RT kernel, the original code could have ended up copying a string out of the freelist. This patch inserts RCU read-side primitives needed to prevent this scenario. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | sched: Fix proc_sched_set_task()Mike Galbraith2010-04-02
|/ | | | | | | | | | | | | | Latencytop clearing sum_exec_runtime via proc_sched_set_task() breaks task_times(). Other places in kernel use nvcsw and nivcsw, which are being cleared as well, Clear task statistics only. Reported-by: Török Edwin <edwintorok@gmail.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1269940193.19286.14.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Convert rq->lock to raw_spinlockThomas Gleixner2009-12-14
| | | | | | | | | | Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
* sched: Remove forced2_migrations statsIngo Molnar2009-12-10
| | | | | | | | | | | | | | | This build warning: kernel/sched.c: In function 'set_task_cpu': kernel/sched.c:2070: warning: unused variable 'old_rq' Made me realize that the forced2_migrations stat looks pretty pointless (and a misnomer) - remove it. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Make tunable scaling style configurableChristian Ehrhardt2009-12-09
| | | | | | | | | | | | | | | | | As scaling now takes place on all kind of cpu add/remove events a user that configures values via proc should be able to configure if his set values are still rescaled or kept whatever happens. As the comments state that log2 was just a second guess that worked the interface is not just designed for on/off, but to choose a scaling type. Currently this allows none, log and linear, but more important it allwos us to keep the interface even if someone has an even better idea how to scale the values. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1259579808-11357-3-git-send-email-ehrhardt@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Discard some old bitsPeter Zijlstra2009-12-09
| | | | | | | | | WAKEUP_RUNNING was an experiment, not sure why that ever ended up being merged... Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Rate-limit newidleMike Galbraith2009-11-04
| | | | | | | | | | Rate limit newidle to migration_cost. It's a win for all stages of sysbench oltp tests. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Add new wakeup preemption mode: WAKEUP_RUNNINGPeter Zijlstra2009-09-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create a new wakeup preemption mode, preempt towards tasks that run shorter on avg. It sets next buddy to be sure we actually run the task we preempted for. Test results: root@twins:~# while :; do :; done & [1] 6537 root@twins:~# while :; do :; done & [2] 6538 root@twins:~# while :; do :; done & [3] 6539 root@twins:~# while :; do :; done & [4] 6540 root@twins:/home/peter# ./latt -c4 sleep 4 Entries: 48 (clients=4) Averages: ------------------------------ Max 4750 usec Avg 497 usec Stdev 737 usec root@twins:/home/peter# echo WAKEUP_RUNNING > /debug/sched_features root@twins:/home/peter# ./latt -c4 sleep 4 Entries: 48 (clients=4) Averages: ------------------------------ Max 14 usec Avg 5 usec Stdev 3 usec Disabled by default - needs more testing. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <new-submission>
* sched: Provide iowait countersArjan van de Ven2009-09-02
| | | | | | | | | | | | | | | | | | For counting how long an application has been waiting for (disk) IO, there currently is only the HZ sample driven information available, while for all other counters in this class, a high resolution version is available via CONFIG_SCHEDSTATS. In order to make an improved bootchart tool possible, we also need a higher resolution version of the iowait time. This patch below adds this scheduler statistic to the kernel. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4A64B813.1080506@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Hide runqueues from direct refer at source code levelHitoshi Mitake2009-06-17
| | | | | | | | | | There are some points which refer the per-cpu value "runqueues" directly. sched.c provides nice abstraction, such as cpu_rq() and this_rq(), so we should use these macros when looking runqueues. Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> LKML-Reference: <20090617.222055.374768827975756908.mitake@dcl.info.waseda.ac.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove unused fields from struct rqLuis Henriques2009-03-24
| | | | | | | | | | | | | | | | | | | | | | Impact: cleanup, new schedstat ABI Since they are used on in statistics and are always set to zero, the following fields from struct rq have been removed: yld_exp_empty, yld_act_empty and yld_both_empty. Both Sched Debug and SCHEDSTAT_VERSION versions has also been incremented since ABIs have been changed. The schedtop tool has been updated to properly handle new version of schedstat: http://rt.wiki.kernel.org/index.php/Schedtop_utility Signed-off-by: Luis Henriques <henrix@sapo.pt> Acked-by: Gregory Haskins <ghaskins@novell.com> Acked-by: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090324221002.GA10061@hades.domain.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: jiffies not printed per CPULuis Henriques2009-03-18
| | | | | | | | | | The jiffies value was being printed for each CPU, which does not seem to make sense. Moved jiffies to system section. Signed-off-by: Luis Henriques <henrix@sapo.pt> Acked-by: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090318000425.GA2228@hades.domain.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: introduce avg_wakeupPeter Zijlstra2009-01-15
| | | | | | | | | | | | Introduce a new avg_wakeup statistic. avg_wakeup is a measure of how frequently a task wakes up other tasks, it represents the average time between wakeups, with a limit of avg_runtime for when it doesn't wake up anybody. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: partly revert "sched debug: remove NULL checking in print_cfs_rt_rq()"Li Zefan2009-01-10
| | | | | | | | | | | Impact: avoid accessing NULL tg.css->cgroup In commit 0a0db8f5c9d4bbb9bbfcc2b6cb6bce2d0ef4d73d, I removed checking NULL tg.css->cgroup, but I realized I was wrong when I found reading /proc/sched_debug can race with cgroup_create(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: add uid information to sched_debug for CONFIG_USER_SCHEDArun R Bharadwaj2008-12-01
| | | | | | | | | | Impact: extend information in /proc/sched_debug This patch adds uid information in sched_debug for CONFIG_USER_SCHED Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'linus' into sched/coreIngo Molnar2008-11-19
|\ | | | | | | | | Conflicts: kernel/Makefile
| * sched: fix kernel warning on /proc/sched_debug accessIngo Molnar2008-11-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Luis Henriques reported that with CONFIG_PREEMPT=y + CONFIG_PREEMPT_DEBUG=y + CONFIG_SCHED_DEBUG=y + CONFIG_LATENCYTOP=y enabled, the following warning triggers when using latencytop: > [ 775.663239] BUG: using smp_processor_id() in preemptible [00000000] code: latencytop/6585 > [ 775.663303] caller is native_sched_clock+0x3a/0x80 > [ 775.663314] Pid: 6585, comm: latencytop Tainted: G W 2.6.28-rc4-00355-g9c7c354 #1 > [ 775.663322] Call Trace: > [ 775.663343] [<ffffffff803a94e4>] debug_smp_processor_id+0xe4/0xf0 > [ 775.663356] [<ffffffff80213f7a>] native_sched_clock+0x3a/0x80 > [ 775.663368] [<ffffffff80213e19>] sched_clock+0x9/0x10 > [ 775.663381] [<ffffffff8024550d>] proc_sched_show_task+0x8bd/0x10e0 > [ 775.663395] [<ffffffff8034466e>] sched_show+0x3e/0x80 > [ 775.663408] [<ffffffff8031039b>] seq_read+0xdb/0x350 > [ 775.663421] [<ffffffff80368776>] ? security_file_permission+0x16/0x20 > [ 775.663435] [<ffffffff802f4198>] vfs_read+0xc8/0x170 > [ 775.663447] [<ffffffff802f4335>] sys_read+0x55/0x90 > [ 775.663460] [<ffffffff8020c67a>] system_call_fastpath+0x16/0x1b > ... This breakage was caused by me via: 7cbaef9: sched: optimize sched_clock() a bit Change the calls to cpu_clock(). Reported-by: Luis Henriques <henrix@sapo.pt>
| * sched: clean up debug infoPeter Zijlstra2008-11-10
| | | | | | | | | | | | | | | | | | | | | | | | | | Impact: clean up and fix debug info printout While looking over the sched_debug code I noticed that we printed the rq schedstats for every cfs_rq, ammend this. Also change nr_spead_over into an int, and fix a little buglet in min_vruntime printing. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: include group statistics in /proc/sched_debugBharata B Rao2008-11-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: extend /proc/sched_debug info Since the statistics of a group entity isn't exported directly from the kernel, it becomes difficult to obtain some of the group statistics. For example, the current method to obtain exec time of a group entity is not always accurate. One has to read the exec times of all the tasks(/proc/<pid>/sched) in the group and add them. This method fails (or becomes difficult) if we want to collect stats of a group over a duration where tasks get created and terminated. This patch makes it easier to obtain group stats by directly including them in /proc/sched_debug. Stats like group exec time would help user programs (like LTP) to accurately measure the group fairness. An example output of group stats from /proc/sched_debug: cfs_rq[3]:/3/a/1 .exec_clock : 89.598007 .MIN_vruntime : 0.000001 .min_vruntime : 256300.970506 .max_vruntime : 0.000001 .spread : 0.000000 .spread0 : -25373.372248 .nr_running : 0 .load : 0 .yld_exp_empty : 0 .yld_act_empty : 0 .yld_both_empty : 0 .yld_count : 4474 .sched_switch : 0 .sched_count : 40507 .sched_goidle : 12686 .ttwu_count : 15114 .ttwu_local : 11950 .bkl_count : 67 .nr_spread_over : 0 .shares : 0 .se->exec_start : 113676.727170 .se->vruntime : 1592.612714 .se->sum_exec_runtime : 89.598007 .se->wait_start : 0.000000 .se->sleep_start : 0.000000 .se->block_start : 0.000000 .se->sleep_max : 0.000000 .se->block_max : 0.000000 .se->exec_max : 1.000282 .se->slice_max : 1.999750 .se->wait_max : 54.981093 .se->wait_sum : 217.610521 .se->wait_count : 50 .se->load.weight : 2 Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Acked-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched debug: remove NULL checking in print_cfs/rt_rq()Li Zefan2008-11-04
|/ | | | | | | | | | | | | | Impact: cleanup cfs->tg is initialized in init_tg_cfs_entry() with tg != NULL, and will never be invalidated to NULL. And the underlying cgroup of a valid task_group is always valid. Same for rt->tg. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: change sched_debug's mode to 0444Li Zefan2008-10-30
| | | | | | | | | | Impact: change /proc/sched/debug from rw-r--r-- to r--r--r-- /proc/sched_debug is read-only. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* [PATCH] signal, procfs: some lock_task_sighand() users do not need ↵Lai Jiangshan2008-10-09
| | | | | | | | | | | | | | | | | | | | | rcu_read_lock() lock_task_sighand() make sure task->sighand is being protected, so we do not need rcu_read_lock(). [ exec() will get task->sighand->siglock before change task->sighand! ] But code using rcu_read_lock() _just_ to protect lock_task_sighand() only appear in procfs. (and some code in procfs use lock_task_sighand() without such redundant protection.) Other subsystem may put lock_task_sighand() into rcu_read_lock() critical region, but these rcu_read_lock() are used for protecting "for_each_process()", "find_task_by_vpid()" etc. , not for protecting lock_task_sighand(). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> [ok from Oleg] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* sched: add full schedstats to /proc/sched_debugPeter Zijlstra2008-06-27
| | | | | | | | | show all the schedstats in /debug/sched_debug as well. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: revert revert of: fair-group: SMP-nice for group schedulingPeter Zijlstra2008-06-27
| | | | | | | | | | | | Try again.. Initial commit: 18d95a2832c1392a2d63227a7a6d433cb9f2037e Revert: 6363ca57c76b7b83639ca8c83fc285fa26a7880e Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: debug: add some rt debug outputPeter Zijlstra2008-06-20
| | | | | | Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Daniel K." <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* revert ("sched: fair-group: SMP-nice for group scheduling")Ingo Molnar2008-05-29
| | | | | | | | | | | | | | | | | | | | | Yanmin Zhang reported: Comparing with 2.6.25, volanoMark has big regression with kernel 2.6.26-rc1. It's about 50% on my 8-core stoakley, 16-core tigerton, and Itanium Montecito. With bisect, I located the following patch: | 18d95a2832c1392a2d63227a7a6d433cb9f2037e is first bad commit | commit 18d95a2832c1392a2d63227a7a6d433cb9f2037e | Author: Peter Zijlstra <a.p.zijlstra@chello.nl> | Date: Sat Apr 19 19:45:00 2008 +0200 | | sched: fair-group: SMP-nice for group scheduling Revert it so that we get v2.6.25 behavior. Bisected-by: Yanmin Zhang <yanmin_zhang@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCKPeter Zijlstra2008-05-05
| | | | | | | | | | | | | | | | | | | | | | this replaces the rq->clock stuff (and possibly cpu_clock()). - architectures that have an 'imperfect' hardware clock can set CONFIG_HAVE_UNSTABLE_SCHED_CLOCK - the 'jiffie' window might be superfulous when we update tick_gtod before the __update_sched_clock() call in sched_clock_tick() - cpu_clock() might be implemented as: sched_clock_cpu(smp_processor_id()) if the accuracy proves good enough - how far can TSC drift in a single jiffie when considering the filtering and idle hooks? [ mingo@elte.hu: various fixes and cleanups ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* rename div64_64 to div64_u64Roman Zippel2008-05-01
| | | | | | | | | | | | | | | | | | | | | Rename div64_64 to div64_u64 to make it consistent with the other divide functions, so it clearly includes the type of the divide. Move its definition to math64.h as currently no architecture overrides the generic implementation. They can still override it of course, but the duplicated declarations are avoided. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: Avi Kivity <avi@qumranet.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "David S. Miller" <davem@davemloft.net> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: use non-racy method for proc entries creationDenis V. Lunev2008-04-29
| | | | | | | | | | | | Use proc_create()/proc_create_data() to make sure that ->proc_fops and ->data be setup before gluing PDE to main tree. Signed-off-by: Denis V. Lunev <den@openvz.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: build fixIngo Molnar2008-04-19
| | | | Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: debug: add some debug code to handle the full hierarchyPeter Zijlstra2008-04-19
| | | | | | | | | | | Add some extra debug output so we can get a better overview of the full hierarchy. We print the cgroup path after each cfs_rq, so we can see what group we're looking at. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove sysctl_sched_batch_wakeup_granularityIngo Molnar2008-04-19
| | | | | | it's unused. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: improve affine wakeupsIngo Molnar2008-03-18
| | | | | | | | | | | | | | | | | improve affine wakeups. Maintain the 'overlap' metric based on CFS's sum_exec_runtime - which means the amount of time a task executes after it wakes up some other task. Use the 'overlap' for the wakeup decisions: if the 'overlap' is short, it means there's strong workload coupling between this task and the woken up task. If the 'overlap' is large then the workload is decoupled and the scheduler will move them to separate CPUs more easily. ( Also slightly move the preempt_check within try_to_wake_up() - this has no effect on functionality but allows 'early wakeups' (for still-on-rq tasks) to be correctly accounted as well.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: keep total / count stats in addition to the max forArjan van de Ven2008-01-25
| | | | | | | | | | | | Right now, the linux kernel (with scheduler statistics enabled) keeps track of the maximum time a process is waiting to be scheduled. While the maximum is a very useful metric, tracking average and total is equally useful (at least for latencytop) to figure out the accumulated effect of scheduler delays. The accumulated effect is important to judge the performance impact of scheduler tuning/behavior. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: monitor clock underflows in /proc/sched_debugGuillaume Chazarain2008-01-25
| | | | | | | We monitor clock overflows, let's also monitor clock underflows. Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix gcc warningsIngo Molnar2007-12-30
| | | | | | | | | | | | | | | | | | | | | | | | | Meelis Roos reported these warnings on sparc64: CC kernel/sched.o In file included from kernel/sched.c:879: kernel/sched_debug.c: In function 'nsec_high': kernel/sched_debug.c:38: warning: comparison of distinct pointer types lacks a cast the debug check in do_div() is over-eager here, because the long long is always positive in these places. Mark this by casting them to unsigned long long. no change in code output: text data bss dec hex filename 51471 6582 376 58429 e43d sched.o.before 51471 6582 376 58429 e43d sched.o.after md5: 7f7729c111f185bf3ccea4d542abc049 sched.o.before.asm 7f7729c111f185bf3ccea4d542abc049 sched.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up overlong line in kernel/sched_debug.cIngo Molnar2007-11-28
| | | | | | clean up overlong line in kernel/sched_debug.c. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: bump version of kernel/sched_debug.cIngo Molnar2007-11-26
| | | | | | | bump version of kernel/sched_debug.c and remove CFS version information from it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: reintroduce the sched_min_granularity tunablePeter Zijlstra2007-11-09
| | | | | | | | | | | | | | | we lost the sched_min_granularity tunable to a clever optimization that uses the sched_latency/min_granularity ratio - but the ratio is quite unintuitive to users and can also crash the kernel if the ratio is set to 0. So reintroduce the min_granularity tunable, while keeping the ratio maintained internally. no functionality changed. [ mingo@elte.hu: some fixlets. ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix unconditional irq lockPeter Zijlstra2007-10-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Lockdep noticed that this lock can also be taken from hardirq context, and can thus not unconditionally disable/enable irqs. WARNING: at kernel/lockdep.c:2033 trace_hardirqs_on() [show_trace_log_lvl+26/48] show_trace_log_lvl+0x1a/0x30 [show_trace+18/32] show_trace+0x12/0x20 [dump_stack+22/32] dump_stack+0x16/0x20 [trace_hardirqs_on+405/416] trace_hardirqs_on+0x195/0x1a0 [_read_unlock_irq+34/48] _read_unlock_irq+0x22/0x30 [sched_debug_show+2615/4224] sched_debug_show+0xa37/0x1080 [show_state_filter+326/368] show_state_filter+0x146/0x170 [sysrq_handle_showstate+10/16] sysrq_handle_showstate+0xa/0x10 [__handle_sysrq+123/288] __handle_sysrq+0x7b/0x120 [handle_sysrq+40/64] handle_sysrq+0x28/0x40 [kbd_event+1045/1680] kbd_event+0x415/0x690 [input_pass_event+206/208] input_pass_event+0xce/0xd0 [input_handle_event+170/928] input_handle_event+0xaa/0x3a0 [input_event+95/112] input_event+0x5f/0x70 [atkbd_interrupt+434/1456] atkbd_interrupt+0x1b2/0x5b0 [serio_interrupt+59/128] serio_interrupt+0x3b/0x80 [i8042_interrupt+263/576] i8042_interrupt+0x107/0x240 [handle_IRQ_event+40/96] handle_IRQ_event+0x28/0x60 [handle_edge_irq+175/320] handle_edge_irq+0xaf/0x140 [do_IRQ+64/128] do_IRQ+0x40/0x80 [common_interrupt+46/52] common_interrupt+0x2e/0x34 Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: reduce schedstat variable overhead a bitKen Chen2007-10-18
| | | | | | | | | | | | | | | | | schedstat is useful in investigating CPU scheduler behavior. Ideally, I think it is beneficial to have it on all the time. However, the cost of turning it on in production system is quite high, largely due to number of events it collects and also due to its large memory footprint. Most of the fields probably don't need to be full 64-bit on 64-bit arch. Rolling over 4 billion events will most like take a long time and user space tool can be made to accommodate that. I'm proposing kernel to cut back most of variable width on 64-bit system. (note, the following patch doesn't affect 32-bit system). Signed-off-by: Ken Chen <kenchen@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Make scheduler debug file operations constArjan van de Ven2007-10-15
| | | | | | | | | | In general, struct file_operations are const in the kernel, to not have false cacheline sharing and to catch bugs at compiletime with accidental writes to them. The new scheduler code introduces a new non-const one; fix this up. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: debug, improve migration statisticsIngo Molnar2007-10-15
| | | | | | | add new migration statistics when SCHED_DEBUG and SCHEDSTATS is enabled. Available in /proc/<PID>/sched. Signed-off-by: Ingo Molnar <mingo@elte.hu>
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