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"It contains lots of scheduler updates from lots of people - hopefully the last big one for quite some time," began Ingo Molnar, describing his merge request for the linux-2.6-sched git tree. He continued, "most of the focus was on performance (both micro-performance and scalability/balancing), but there's the fair-scheduling feature now Kconfig selectable too. Find the shortlog below." Ingo noted, "code that is touched outside of the scheduler: the KVM bits were acked by Avi, the net/unix change is trivial and only affects sync wakeups, ditto the fs/pipe.c changes - but i can push those separately if it needs an ack from David first." He then concluded:
"Testing status: the changes are chronological and all the interactivity-impacting changes are near the head of the queue and most of them were done weeks ago, and were thus part of the CFS-v22 backport series - which was tested by many people. There are no known regressions at the moment. It's all fully bisectable."
From: Ingo Molnar Subject: [git pull] scheduler updates for v2.6.24 Date: Oct 15, 7:17 am 2007 Linus, please pull the latest scheduler git tree from: git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched.git It contains lots of scheduler updates from lots of people - hopefully the last big one for quite some time. Most of the focus was on performance (both micro-performance and scalability/balancing), but there's the fair-scheduling feature now Kconfig selectable too. Find the shortlog below. Code that is touched outside of the scheduler: the KVM bits were acked by Avi, the net/unix change is trivial and only affects sync wakeups, ditto the fs/pipe.c changes - but i can push those separately if it needs an ack from David first. ABI/API changes: - new CONFIG_FAIR_USER_SCHED and /sys/kernel/uids/ + uevent API. - /proc/stat and /proc/<pid>/stat changes for guest-CPU usage [KVM] - /proc/sched_debug formats changed/enhanced Testing status: the changes are chronological and all the interactivity-impacting changes are near the head of the queue and most of them were done weeks ago, and were thus part of the CFS-v22 backport series - which was tested by many people. There are no known regressions at the moment. It's all fully bisectable. Thanks, Ingo ------------------> Alexey Dobriyan (1): sched: uninline scheduler Andi Kleen (4): sched: cleanup: remove unnecessary gotos sched: cleanup: refactor common code of sleep_on / wait_for_completion sched: cleanup: refactor normalize_rt_tasks sched: remove stale comment from sched_group_set_shares() Arjan van de Ven (1): Make scheduler debug file operations const Dhaval Giani (1): sched: group scheduling, sysfs tunables Dmitry Adamushko (14): sched: clean up struct load_stat sched: clean up schedstat block in dequeue_entity() sched: sched_setscheduler() fix sched: add set_curr_task() calls sched: do not keep current in the tree and get rid of sched_entity::fair_key sched: optimize task_new_fair() sched: simplify sched_class::yield_task() sched: rework enqueue/dequeue_entity() to get rid of set_curr_task() sched: yield fix sched: fix __pick_next_entity() sched: tidy up SCHED_RR sched: cleanup, remove calc_weighted() sched: cleanup, make dequeue_entity() and update_stats_wait_end() similar sched: fix group scheduling for SCHED_BATCH Gautham R Shenoy (1): sched: fix rt ptracer monopolizing CPU Hiroshi Shimamoto (1): sched: clean up sched_fork() Ingo Molnar (71): sched: fix sysctl_sched_child_runs_first flag sched: resched task in task_new_fair() sched: small sched_debug cleanup sched: debug: track maximum 'slice' sched: uniform tunings sched: use constants if !CONFIG_SCHED_DEBUG sched: remove stat_gran sched: remove precise CPU load sched: remove precise CPU load calculations #2 sched: track cfs_rq->curr on !group-scheduling too sched: cleanup: simplify cfs_rq_curr() methods sched: uninline __enqueue_entity()/__dequeue_entity() sched: speed up update_load_add/_sub() sched: clean up calc_weighted() sched: introduce se->vruntime sched: move sched_feat() definitions sched: optimize vruntime based scheduling sched: simplify check_preempt() methods sched: wakeup granularity increase sched: add se->vruntime debugging sched: remove SCHED_FEAT_SKIP_INITIAL sched: add more vruntime statistics sched: debug: update exec_clock only when SCHED_DEBUG sched: remove wait_runtime limit sched: remove wait_runtime fields and features sched: x86: allow single-depth wchan output sched: fix delay accounting performance regression sched: prettify /proc/sched_debug output sched: enhance debug output sched: kernel/sched_fair.c whitespace cleanups sched: fair-group sched, cleanups sched: enable CONFIG_FAIR_GROUP_SCHED=y by default sched debug: BKL usage statistics sched: remove unneeded tunables sched debug: print settings sched debug: more width for parameter printouts sched: entity_key() fix sched: remove condition from set_task_cpu() sched: remove last_min_vruntime effect sched: undo some of the recent changes sched: fix sign check error in place_entity() sched: fix sched_fork() sched: remove set_leftmost() sched: clean up schedstats, cnt -> count sched: cleanup, remove stale comment sched: mark scheduling classes as const sched: whitespace cleanups sched: vslice fixups for non-0 nice levels sched: optimize schedule() a bit on SMP sched: tweak wakeup granularity sched: run sched_domain_debug() if CONFIG_SCHED_DEBUG=y sched: break out if printing a warning in sched_domain_debug() sched: style cleanup sched: kfree(NULL) is valid sched: cleanup: rename SCHED_FEAT_USE_TREE_AVG to SCHED_FEAT_TREE_AVG sched: cleanup: rename task_grp to task_group sched: cleanup: function prototype cleanups sched: fix: move the CPU check into ->task_new_fair() sched: update comment sched: clean up is_migration_thread() sched: do not normalize kernel threads via SysRq-N sched: do not wakeup-preempt with SCHED_BATCH tasks sched: speed up context-switches a bit sched: reintroduce cache-hot affinity sched: debug: increase width of debug line sched: debug, improve migration statistics sched: allow the immediate migration of cache-cold tasks sched: reintroduce topology.h tunings sched: enable wake-idle on CONFIG_SCHED_MC=y sched: affine sync wakeups sched: sync wakeups preempt too Laurent Vivier (4): sched: guest CPU accounting: add guest-CPU /proc/stat field sched: guest CPU accounting: add guest-CPU /proc/<pid>/stat fields sched: guest CPU accounting: maintain stats in account_system_time() sched: guest CPU accounting: maintain guest state in KVM Matthias Kaehlcke (1): sched: use list_for_each_entry_safe() in __wake_up_common() Mike Galbraith (4): sched: fix SMP migration latencies sched: fix formatting of /proc/sched_debug sched: cleanup, remove the TASK_NONINTERACTIVE flag sched: prevent wakeup over-scheduling Milton Miller (5): sched: domain sysctl fixes: use kcalloc() sched: domain sysctl fixes: use for_each_online_cpu() sched: domain sysctl fixes: unregister the sysctl table before domains sched: domain sysctl fixes: do not crash on allocation failure sched: domain sysctl fixes: add terminator comment Paul E. McKenney (1): sched: export cpu_clock() Peter Williams (2): sched: reduce balance-tasks overhead sched: isolate SMP balancing code a bit more Peter Zijlstra (16): sched: simplify SCHED_FEAT_* code sched: new task placement for vruntime sched: simplify adaptive latency sched: clean up new task placement sched: add tree based averages sched: handle vruntime 64-bit overflow sched: better min_vruntime tracking sched: add vslice sched debug: check spread sched: max_vruntime() simplification sched: clean up min_vruntime use sched: speed up and simplify vslice calculations sched: another wakeup_granularity fix sched: disable sleeper_fairness on SCHED_BATCH sched: disable forced preemption by default sched: activate task_hot() only on fair-scheduled tasks S.Caglar Onur (1): sched debug: BKL usage statistics, fix Srivatsa Vaddagiri (13): sched: group-scheduler core sched: revert recent removal of set_curr_task() sched: fix minor bug in yield sched: print nr_running and load in /proc/sched_debug sched: print &rq->cfs stats sched: clean up code under CONFIG_FAIR_GROUP_SCHED sched: add fair-user scheduler sched: group scheduler wakeup latency fix sched: group scheduler SMP migration fix sched: group scheduler, fix coding style issues sched: group scheduler, fix bloat sched: group scheduler, fix latency sched: generate uevents for user creation/destruction Zou Nan hai (1): sched: some proc entries are missed in sched_domain sys_ctl debug code Documentation/sched-design-CFS.txt | 67 + arch/i386/Kconfig | 11 drivers/kvm/kvm.h | 10 drivers/kvm/kvm_main.c | 2 fs/pipe.c | 9 fs/proc/array.c | 17 fs/proc/base.c | 2 fs/proc/proc_misc.c | 15 include/linux/kernel_stat.h | 1 include/linux/sched.h | 108 +- include/linux/topology.h | 5 init/Kconfig | 21 kernel/delayacct.c | 2 kernel/exit.c | 6 kernel/fork.c | 3 kernel/ksysfs.c | 8 kernel/sched.c | 1526 +++++++++++++++++++++---------------- kernel/sched_debug.c | 282 ++++-- kernel/sched_fair.c | 859 ++++++++------------ kernel/sched_idletask.c | 26 kernel/sched_rt.c | 51 - kernel/sched_stats.h | 28 kernel/sysctl.c | 37 kernel/user.c | 249 +++++- net/unix/af_unix.c | 4 25 files changed, 1998 insertions(+), 1351 deletions(-) -
From: Ingo Molnar Subject: Re: [git pull] scheduler updates for v2.6.24 Date: Oct 15, 8:04 am 2007 * Ingo Molnar <mingo@elte.hu> wrote: > Linus, please pull the latest scheduler git tree from: > > git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched.git oops, these two cleanups caused build failures in some config variants: > sched: reduce balance-tasks overhead > sched: isolate SMP balancing code a bit more so i dropped them and re-pushed. New shortlog below. Ingo ------------------> Alexey Dobriyan (1): sched: uninline scheduler Andi Kleen (4): sched: cleanup: remove unnecessary gotos sched: cleanup: refactor common code of sleep_on / wait_for_completion sched: cleanup: refactor normalize_rt_tasks sched: remove stale comment from sched_group_set_shares() Arjan van de Ven (1): Make scheduler debug file operations const Dhaval Giani (1): sched: group scheduling, sysfs tunables Dmitry Adamushko (14): sched: clean up struct load_stat sched: clean up schedstat block in dequeue_entity() sched: sched_setscheduler() fix sched: add set_curr_task() calls sched: do not keep current in the tree and get rid of sched_entity::fair_key sched: optimize task_new_fair() sched: simplify sched_class::yield_task() sched: rework enqueue/dequeue_entity() to get rid of set_curr_task() sched: yield fix sched: fix __pick_next_entity() sched: tidy up SCHED_RR sched: cleanup, remove calc_weighted() sched: cleanup, make dequeue_entity() and update_stats_wait_end() similar sched: fix group scheduling for SCHED_BATCH Gautham R Shenoy (1): sched: fix rt ptracer monopolizing CPU Hiroshi Shimamoto (1): sched: clean up sched_fork() Ingo Molnar (71): sched: fix sysctl_sched_child_runs_first flag sched: resched task in task_new_fair() sched: small sched_debug cleanup sched: debug: track maximum 'slice' sched: uniform tunings sched: use constants if !CONFIG_SCHED_DEBUG sched: remove stat_gran sched: remove precise CPU load sched: remove precise CPU load calculations #2 sched: track cfs_rq->curr on !group-scheduling too sched: cleanup: simplify cfs_rq_curr() methods sched: uninline __enqueue_entity()/__dequeue_entity() sched: speed up update_load_add/_sub() sched: clean up calc_weighted() sched: introduce se->vruntime sched: move sched_feat() definitions sched: optimize vruntime based scheduling sched: simplify check_preempt() methods sched: wakeup granularity increase sched: add se->vruntime debugging sched: remove SCHED_FEAT_SKIP_INITIAL sched: add more vruntime statistics sched: debug: update exec_clock only when SCHED_DEBUG sched: remove wait_runtime limit sched: remove wait_runtime fields and features sched: x86: allow single-depth wchan output sched: fix delay accounting performance regression sched: prettify /proc/sched_debug output sched: enhance debug output sched: kernel/sched_fair.c whitespace cleanups sched: fair-group sched, cleanups sched: enable CONFIG_FAIR_GROUP_SCHED=y by default sched debug: BKL usage statistics sched: remove unneeded tunables sched debug: print settings sched debug: more width for parameter printouts sched: entity_key() fix sched: remove condition from set_task_cpu() sched: remove last_min_vruntime effect sched: undo some of the recent changes sched: fix sign check error in place_entity() sched: fix sched_fork() sched: remove set_leftmost() sched: clean up schedstats, cnt -> count sched: cleanup, remove stale comment sched: mark scheduling classes as const sched: whitespace cleanups sched: vslice fixups for non-0 nice levels sched: optimize schedule() a bit on SMP sched: tweak wakeup granularity sched: run sched_domain_debug() if CONFIG_SCHED_DEBUG=y sched: break out if printing a warning in sched_domain_debug() sched: style cleanup sched: kfree(NULL) is valid sched: cleanup: rename SCHED_FEAT_USE_TREE_AVG to SCHED_FEAT_TREE_AVG sched: cleanup: rename task_grp to task_group sched: cleanup: function prototype cleanups sched: fix: move the CPU check into ->task_new_fair() sched: update comment sched: clean up is_migration_thread() sched: do not normalize kernel threads via SysRq-N sched: do not wakeup-preempt with SCHED_BATCH tasks sched: speed up context-switches a bit sched: reintroduce cache-hot affinity sched: debug: increase width of debug line sched: debug, improve migration statistics sched: allow the immediate migration of cache-cold tasks sched: reintroduce topology.h tunings sched: enable wake-idle on CONFIG_SCHED_MC=y sched: affine sync wakeups sched: sync wakeups preempt too Laurent Vivier (4): sched: guest CPU accounting: add guest-CPU /proc/stat field sched: guest CPU accounting: add guest-CPU /proc/<pid>/stat fields sched: guest CPU accounting: maintain stats in account_system_time() sched: guest CPU accounting: maintain guest state in KVM Matthias Kaehlcke (1): sched: use list_for_each_entry_safe() in __wake_up_common() Mike Galbraith (4): sched: fix SMP migration latencies sched: fix formatting of /proc/sched_debug sched: cleanup, remove the TASK_NONINTERACTIVE flag sched: prevent wakeup over-scheduling Milton Miller (5): sched: domain sysctl fixes: use kcalloc() sched: domain sysctl fixes: use for_each_online_cpu() sched: domain sysctl fixes: unregister the sysctl table before domains sched: domain sysctl fixes: do not crash on allocation failure sched: domain sysctl fixes: add terminator comment Paul E. McKenney (1): sched: export cpu_clock() Peter Zijlstra (16): sched: simplify SCHED_FEAT_* code sched: new task placement for vruntime sched: simplify adaptive latency sched: clean up new task placement sched: add tree based averages sched: handle vruntime 64-bit overflow sched: better min_vruntime tracking sched: add vslice sched debug: check spread sched: max_vruntime() simplification sched: clean up min_vruntime use sched: speed up and simplify vslice calculations sched: another wakeup_granularity fix sched: disable sleeper_fairness on SCHED_BATCH sched: disable forced preemption by default sched: activate task_hot() only on fair-scheduled tasks S.Caglar Onur (1): sched debug: BKL usage statistics, fix Srivatsa Vaddagiri (13): sched: group-scheduler core sched: revert recent removal of set_curr_task() sched: fix minor bug in yield sched: print nr_running and load in /proc/sched_debug sched: print &rq->cfs stats sched: clean up code under CONFIG_FAIR_GROUP_SCHED sched: add fair-user scheduler sched: group scheduler wakeup latency fix sched: group scheduler SMP migration fix sched: group scheduler, fix coding style issues sched: group scheduler, fix bloat sched: group scheduler, fix latency sched: generate uevents for user creation/destruction Zou Nan hai (1): sched: some proc entries are missed in sched_domain sys_ctl debug code Documentation/sched-design-CFS.txt | 67 + arch/i386/Kconfig | 11 drivers/kvm/kvm.h | 10 drivers/kvm/kvm_main.c | 2 fs/pipe.c | 9 fs/proc/array.c | 17 fs/proc/base.c | 2 fs/proc/proc_misc.c | 15 include/linux/kernel_stat.h | 1 include/linux/sched.h | 99 +- include/linux/topology.h | 5 init/Kconfig | 21 kernel/delayacct.c | 2 kernel/exit.c | 6 kernel/fork.c | 3 kernel/ksysfs.c | 8 kernel/sched.c | 1444 +++++++++++++++++++++---------------- kernel/sched_debug.c | 282 ++++--- kernel/sched_fair.c | 811 ++++++++------------ kernel/sched_idletask.c | 8 kernel/sched_rt.c | 19 kernel/sched_stats.h | 28 kernel/sysctl.c | 37 kernel/user.c | 249 ++++++ net/unix/af_unix.c | 4 25 files changed, 1872 insertions(+), 1288 deletions(-) -
From: Andrew Morton Subject: Re: [git pull] scheduler updates for v2.6.24 Date: Oct 15, 11:35 am 2007 On Mon, 15 Oct 2007 16:17:23 +0200 Ingo Molnar <mingo@elte.hu> wrote: > Linus, please pull the latest scheduler git tree from: > > git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched.git Did Paul Jackson's crash get fixed? -
From: Ingo Molnar Subject: Re: [git pull] scheduler updates for v2.6.24 Date: Oct 15, 11:53 am 2007 * Andrew Morton <akpm@linux-foundation.org> wrote: > On Mon, 15 Oct 2007 16:17:23 +0200 > Ingo Molnar <mingo@elte.hu> wrote: > > > Linus, please pull the latest scheduler git tree from: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched.git > > Did Paul Jackson's crash get fixed? yes - that crash was a showstopper that was holding up the pull request for 2 days. Paul bisected it down to the culprit and the fix was to do this in wake_up_new_task(): - if (!p->sched_class->task_new || !current->se.on_rq) { + if (!p->sched_class->task_new || !current->se.on_rq || !rq->cfs.curr) { (during early bootup the cfs_rq has no curr pointer yet.) It's not clear why this race did not trigger earlier. (and the two checks can probably be consolidated into a single "!rq->cfs.curr" condition.) Ingo -
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Compare?
Good.
But how does it compare against other algorithms and implementation?
Example, 2.6.22, -ck, FreeBSD, DragonFlyBSD, Windows, Plan 9, etc?
I don't think you can
I don't think you can compare schedulers so easily...
linux on linux, the scheduler performance is polluted by other subsystems just by passing from the .22 to the .23, as someone noted in the benchmarks. I think that a scheduler test couldn't really make sense from one system to another.
you could still benchmarks the system as whole, but then the scheduling will be obfuscated by other factors...