From: Mike Galbraith <efault@gmx.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Serge Belyshev <belyshev@depni.sinp.msu.ru>,
Con Kolivas <kernel@kolivas.org>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: Epic regression in throughput since v2.6.23
Date: Sun, 13 Sep 2009 21:17:52 +0200 [thread overview]
Message-ID: <1252869472.14621.24.camel@marge.simson.net> (raw)
In-Reply-To: <20090913154744.GA27066@elte.hu>
On Sun, 2009-09-13 at 17:47 +0200, Ingo Molnar wrote:
> * Serge Belyshev <belyshev@depni.sinp.msu.ru> wrote:
>
> > Note that the disabling NEW_FAIR_SLEEPERS doesn't fix 3%
> > regression from v2.6.23, but instead makes "make -j4" runtime
> > another 2% worse (27.05 -> 27.72).
>
> ok - thanks for the numbers, will have a look.
Seems NEXT_BUDDY is hurting the -j4 build.
LAST_BUDDY helps, which makes some sense.. if a task has heated up
cache, and is wakeup preempted by a fast mover (kthread, make..), it can
get the CPU back with still toasty data. Hm. If NEXT_BUDDY is on, that
benefit would likely be frequently destroyed too, because NEXT_BUDDY is
preferred over LAST_BUDDY.
Anyway, I'm thinking of tracking forks/sec as a means of detecting the
fork/exec load. Or, maybe just enable it when there's > 1 buddy pair
running.. or something. After all, NEXT_BUDDY is about scalability, and
make -j4 on a quad surely doesn't need any scalability help :)
Performance counter stats for 'make -j4 vmlinux':
stock
111.625198810 seconds time elapsed avg 112.120 1.00
112.209501685 seconds time elapsed
112.528258240 seconds time elapsed
NO_NEXT_BUDDY NO_LAST_BUDDY
109.405064078 seconds time elapsed avg 109.351 .975
108.708076118 seconds time elapsed
109.942346026 seconds time elapsed
NO_NEXT_BUDDY
108.005756718 seconds time elapsed avg 108.064 .963
107.689862679 seconds time elapsed
108.497117555 seconds time elapsed
NO_LAST_BUDDY
110.208717063 seconds time elapsed avg 110.120 .982
110.362412902 seconds time elapsed
109.791359601 seconds time elapsed
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index aa7f841..7cfea64 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1501,7 +1501,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
*/
if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))
set_last_buddy(se);
- set_next_buddy(pse);
+ if (sched_feat(NEXT_BUDDY))
+ set_next_buddy(pse);
/*
* We can come here with TIF_NEED_RESCHED already set from new task
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index e2dc63a..6e7070b 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -13,5 +13,6 @@ SCHED_FEAT(LB_BIAS, 1)
SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
SCHED_FEAT(ASYM_EFF_LOAD, 1)
SCHED_FEAT(WAKEUP_OVERLAP, 0)
+SCHED_FEAT(NEXT_BUDDY, 1)
SCHED_FEAT(LAST_BUDDY, 1)
SCHED_FEAT(OWNER_SPIN, 1)
next prev parent reply other threads:[~2009-09-13 19:17 UTC|newest]
Thread overview: 216+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-06 20:59 BFS vs. mainline scheduler benchmarks and measurements Ingo Molnar
2009-09-07 2:05 ` Frans Pop
2009-09-07 12:16 ` [quad core results] " Ingo Molnar
2009-09-07 12:36 ` Stefan Richter
2009-09-07 13:41 ` Markus Tornqvist
2009-09-07 13:59 ` Ingo Molnar
2009-09-09 5:54 ` Markus Tornqvist
2009-09-07 14:45 ` Arjan van de Ven
2009-09-07 15:20 ` Frans Pop
2009-09-07 15:36 ` Arjan van de Ven
2009-09-07 15:47 ` Frans Pop
2009-09-07 15:24 ` Xavier Bestel
2009-09-07 15:37 ` Arjan van de Ven
2009-09-07 16:00 ` Diego Calleja
2009-09-07 15:34 ` Nikos Chantziaras
2009-09-07 3:38 ` Nikos Chantziaras
2009-09-07 11:01 ` Frederic Weisbecker
2009-09-08 18:15 ` Nikos Chantziaras
2009-09-10 20:25 ` Frederic Weisbecker
2009-09-07 14:40 ` Arjan van de Ven
2009-09-08 7:19 ` Nikos Chantziaras
2009-09-08 8:31 ` Arjan van de Ven
2009-09-08 20:22 ` Frans Pop
2009-09-08 21:10 ` Michal Schmidt
2009-09-08 21:11 ` Frans Pop
2009-09-08 21:40 ` GeunSik Lim
2009-09-08 22:36 ` Frans Pop
2009-09-09 9:53 ` Benjamin Herrenschmidt
2009-09-09 11:14 ` David Newall
2009-09-09 11:32 ` Benjamin Herrenschmidt
2009-09-09 11:55 ` Frans Pop
2009-09-11 1:36 ` Benjamin Herrenschmidt
2009-09-16 18:27 ` Frans Pop
2009-09-17 1:29 ` Benjamin Herrenschmidt
2009-10-01 9:36 ` Frans Pop
2009-09-08 8:38 ` Arjan van de Ven
2009-09-08 10:13 ` Nikos Chantziaras
2009-09-08 11:32 ` Juergen Beisert
2009-09-08 22:00 ` Nikos Chantziaras
2009-09-08 23:20 ` Jiri Kosina
2009-09-08 23:38 ` Nikos Chantziaras
2009-09-08 12:03 ` Theodore Tso
2009-09-08 21:28 ` Nikos Chantziaras
2009-09-08 14:20 ` Arjan van de Ven
2009-09-08 22:53 ` Nikos Chantziaras
2009-09-07 23:54 ` Thomas Fjellstrom
2009-09-08 11:30 ` Nikos Chantziaras
2009-09-07 3:50 ` Con Kolivas
2009-09-07 18:20 ` Jerome Glisse
2009-09-07 9:49 ` Jens Axboe
2009-09-07 10:12 ` Nikos Chantziaras
2009-09-07 10:41 ` Jens Axboe
2009-09-07 11:57 ` Jens Axboe
2009-09-07 14:14 ` Ingo Molnar
2009-09-07 17:38 ` Jens Axboe
2009-09-07 20:44 ` Jens Axboe
2009-09-08 9:13 ` Jens Axboe
2009-09-08 15:23 ` Peter Zijlstra
2009-09-08 20:34 ` Jens Axboe
2009-09-09 6:13 ` Ingo Molnar
2009-09-09 8:34 ` Nikos Chantziaras
2009-09-09 8:52 ` Mike Galbraith
2009-09-09 9:02 ` Peter Zijlstra
2009-09-09 9:18 ` Mike Galbraith
2009-09-09 9:05 ` Nikos Chantziaras
2009-09-09 9:17 ` Peter Zijlstra
2009-09-09 9:40 ` Nikos Chantziaras
2009-09-09 10:17 ` Nikos Chantziaras
2009-09-10 19:45 ` Martin Steigerwald
2009-09-10 20:06 ` Ingo Molnar
2009-09-10 20:39 ` Martin Steigerwald
2009-09-10 20:42 ` Ingo Molnar
2009-09-10 21:19 ` Martin Steigerwald
2009-09-11 9:26 ` Mat
2009-09-12 11:26 ` Martin Steigerwald
2009-09-09 9:10 ` Jens Axboe
2009-09-09 11:54 ` Jens Axboe
2009-09-09 12:20 ` Jens Axboe
2009-09-09 18:04 ` Ingo Molnar
2009-09-09 20:12 ` Nikos Chantziaras
2009-09-09 20:50 ` Jens Axboe
2009-09-10 1:02 ` Con Kolivas
2009-09-10 11:03 ` Jens Axboe
2009-09-10 3:15 ` Mike Galbraith
2009-09-10 6:08 ` Ingo Molnar
2009-09-10 6:40 ` Ingo Molnar
2009-09-10 9:54 ` Jens Axboe
2009-09-10 10:03 ` Ingo Molnar
2009-09-10 10:11 ` Jens Axboe
2009-09-10 10:28 ` Jens Axboe
2009-09-10 10:57 ` Mike Galbraith
2009-09-10 11:09 ` Jens Axboe
2009-09-10 11:21 ` Mike Galbraith
2009-09-10 11:24 ` Jens Axboe
2009-09-10 11:28 ` Mike Galbraith
2009-09-10 11:35 ` Jens Axboe
2009-09-10 11:42 ` Mike Galbraith
2009-09-10 16:02 ` Bret Towe
2009-09-10 16:05 ` Peter Zijlstra
2009-09-10 16:12 ` Bret Towe
2009-09-10 16:26 ` Ingo Molnar
2009-09-10 16:33 ` Bret Towe
2009-09-10 17:03 ` Ingo Molnar
2009-09-10 17:53 ` Nikos Chantziaras
2009-09-10 18:46 ` Ingo Molnar
2009-09-10 18:51 ` [tip:sched/core] sched: Disable NEW_FAIR_SLEEPERS for now tip-bot for Ingo Molnar
2009-09-10 18:57 ` [tip:sched/core] sched: Fix sched::sched_stat_wait tracepoint field tip-bot for Ingo Molnar
2009-09-10 9:48 ` BFS vs. mainline scheduler benchmarks and measurements Jens Axboe
2009-09-10 9:59 ` Ingo Molnar
2009-09-10 10:01 ` Jens Axboe
2009-09-10 6:55 ` Peter Zijlstra
2009-09-10 6:58 ` Jens Axboe
2009-09-10 7:04 ` Ingo Molnar
2009-09-10 9:44 ` Jens Axboe
2009-09-10 9:45 ` Jens Axboe
2009-09-10 13:53 ` Steven Rostedt
2009-09-10 7:33 ` Jens Axboe
2009-09-10 7:49 ` Ingo Molnar
2009-09-10 7:53 ` Jens Axboe
2009-09-10 10:02 ` Ingo Molnar
2009-09-10 10:09 ` Jens Axboe
2009-09-10 18:00 ` [crash, bisected] Re: clocksource: Resolve cpu hotplug dead lock with TSC unstable Ingo Molnar
2009-09-11 7:37 ` Ingo Molnar
2009-09-11 7:48 ` Martin Schwidefsky
2009-09-11 13:33 ` Martin Schwidefsky
2009-09-11 18:22 ` [tip:timers/core] clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crash tip-bot for Martin Schwidefsky
2009-09-14 15:19 ` [crash, bisected] Re: clocksource: Resolve cpu hotplug dead lock with TSC unstable Ingo Molnar
2009-09-14 15:37 ` Martin Schwidefsky
2009-09-14 17:59 ` Martin Schwidefsky
2009-09-10 6:59 ` BFS vs. mainline scheduler benchmarks and measurements Ingo Molnar
2009-09-09 12:48 ` Mike Galbraith
2009-09-09 15:37 ` [tip:sched/core] sched: Turn off child_runs_first tip-bot for Mike Galbraith
2009-09-09 17:57 ` Theodore Tso
2009-09-09 18:08 ` Ingo Molnar
2009-09-09 18:59 ` Chris Friesen
2009-09-09 19:48 ` Pavel Machek
2009-09-09 15:37 ` [tip:sched/core] sched: Re-tune the scheduler latency defaults to decrease worst-case latencies tip-bot for Mike Galbraith
2009-09-12 11:45 ` Martin Steigerwald
2009-09-09 15:37 ` [tip:sched/core] sched: Keep kthreads at default priority tip-bot for Mike Galbraith
2009-09-09 16:55 ` Dmitry Torokhov
2009-09-09 17:06 ` Peter Zijlstra
2009-09-09 17:34 ` Mike Galbraith
2009-09-12 11:48 ` Martin Steigerwald
2009-09-12 12:19 ` Mike Galbraith
2009-09-09 11:52 ` BFS vs. mainline scheduler benchmarks and measurements Nikos Chantziaras
2009-09-07 18:02 ` Avi Kivity
2009-09-07 18:46 ` Jens Axboe
2009-09-07 20:36 ` Ingo Molnar
2009-09-07 20:46 ` Jens Axboe
2009-09-07 21:03 ` Peter Zijlstra
2009-09-07 21:05 ` Jens Axboe
2009-09-07 22:18 ` Ingo Molnar
2009-09-09 7:38 ` Pavel Machek
2009-09-10 12:19 ` latt location (Was Re: BFS vs. mainline scheduler benchmarks and measurements) Jens Axboe
2009-09-07 15:16 ` BFS vs. mainline scheduler benchmarks and measurements Michael Buesch
2009-09-07 18:26 ` Ingo Molnar
2009-09-07 18:47 ` Daniel Walker
2009-09-07 18:51 ` Michael Buesch
2009-09-07 20:57 ` Ingo Molnar
2009-09-07 23:24 ` Pekka Pietikainen
2009-09-08 8:04 ` Ingo Molnar
2009-09-08 8:13 ` Nikos Chantziaras
2009-09-08 10:12 ` Ingo Molnar
2009-09-08 10:40 ` Nikos Chantziaras
2009-09-08 11:35 ` Ingo Molnar
2009-09-08 19:06 ` Nikos Chantziaras
2009-09-08 12:00 ` el_es
2009-09-08 15:45 ` Michael Buesch
2009-09-08 7:48 ` Ingo Molnar
2009-09-08 9:50 ` Benjamin Herrenschmidt
2009-09-08 13:09 ` Ralf Baechle
2009-09-09 1:36 ` Felix Fietkau
2009-09-08 13:09 ` Felix Fietkau
2009-09-09 0:28 ` Benjamin Herrenschmidt
2009-09-09 0:37 ` David Miller
2009-09-08 14:45 ` Michael Buesch
2009-09-18 11:24 ` Ingo Molnar
2009-09-18 14:46 ` Felix Fietkau
2009-09-19 18:01 ` Ingo Molnar
2009-09-19 18:43 ` Felix Fietkau
2009-09-19 19:39 ` Ingo Molnar
2009-09-19 20:15 ` Felix Fietkau
2009-09-19 20:22 ` Ingo Molnar
2009-09-19 20:33 ` Felix Fietkau
2009-09-20 18:10 ` Ingo Molnar
2009-09-08 12:57 ` Epic regression in throughput since v2.6.23 Serge Belyshev
2009-09-08 17:47 ` Jesse Brandeburg
2009-09-08 18:20 ` Nikos Chantziaras
2009-09-08 19:00 ` Jeff Garzik
2009-09-08 19:20 ` Serge Belyshev
2009-09-08 19:26 ` Jeff Garzik
2009-09-08 18:37 ` Nikos Chantziaras
2009-09-08 22:15 ` Serge Belyshev
2009-09-09 15:52 ` Ingo Molnar
2009-09-09 20:49 ` Serge Belyshev
2009-09-09 21:23 ` Cory Fields
2009-09-10 6:53 ` Ingo Molnar
2009-09-10 23:23 ` Serge Belyshev
2009-09-11 6:10 ` Ingo Molnar
2009-09-11 8:55 ` Serge Belyshev
2009-09-13 15:27 ` Serge Belyshev
2009-09-13 15:47 ` Ingo Molnar
2009-09-13 19:17 ` Mike Galbraith [this message]
2009-09-14 6:15 ` Mike Galbraith
2009-09-16 19:45 ` Ingo Molnar
2009-09-16 23:18 ` Serge Belyshev
2009-09-17 4:55 ` [patchlet] " Mike Galbraith
2009-09-17 5:06 ` Mike Galbraith
2009-09-17 7:21 ` Ingo Molnar
2009-09-10 7:43 ` [updated] BFS vs. mainline scheduler benchmarks and measurements Ingo Molnar
2009-09-14 9:46 ` Phoronix CFS vs BFS bencharks Nikos Chantziaras
2009-09-14 11:35 ` Mike Galbraith
[not found] ` <f42384a10909140727k463ff460q3859892dcb79bcc5@mail.gmail.com>
2009-09-14 15:32 ` Mike Galbraith
2009-09-14 19:14 ` Marcin Letyns
2009-09-14 20:49 ` Willy Tarreau
2009-09-15 8:37 ` Mike Galbraith
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