Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752795Ab3HFHrD (ORCPT ); Tue, 6 Aug 2013 03:47:03 -0400 Received: from moutng.kundenserver.de ([212.227.126.171]:53519 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751981Ab3HFHrA (ORCPT ); Tue, 6 Aug 2013 03:47:00 -0400 Message-ID: <1375775172.5412.14.camel@marge.simpson.net> Subject: Re: [PATCH V3]hrtimer: Fix a performance regression by disable reprogramming in remove_hrtimer From: Mike Galbraith To: Peter Zijlstra Cc: Ethan Zhao , Thomas Gleixner , Ingo Molnar , LKML , johlstei@codeaurora.org, Yinghai Lu , Jin Feng , Youquan Song , LenBrown Date: Tue, 06 Aug 2013 09:46:12 +0200 In-Reply-To: <1375774140.5412.9.camel@marge.simpson.net> References: <1374955447-5051-1-git-send-email-ethan.kernel@gmail.com> <20130730093519.GP3008@twins.programming.kicks-ass.net> <1375774140.5412.9.camel@marge.simpson.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Provags-ID: V02:K0:h8ynmWzvg/EFTJEYoAG1Obedg1tVnD/VxbXnbOjyAvn k1SS6eouHWQRgjLa5eF9ga4W0D1kHvSStuKGCdJaOJpB+wsWBF mhLzh2mPrn6KboxTHQA82xYmO3wro7TODPiUQSsxkAYTuC99M3 TrayJzHd9dn1t9ZQ509gPQTMY3khPOZGsmjSEmoH1c0jFjWd/X 5aZJasjrgYFBvLPuoG6s9FDg+vyuUJejctrvbAoFh190P9JgHM V0+E7psm15jTeIuiCgyKk+X3YcXKaJuvnTYOTbRtTKlkJa1rEt G/ZMvQG8CoIEnc15UOM23rLtv2vzM0l5NqtHPohKMW3pCiaZiT Ecghj8bnrAbWRu/CRDjpoLpI8ofT+mSEa1FTc+7FeKjWFYZBaI /hPIiJHTYE5pw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10306 Lines: 200 (CCs Intel folks) On Tue, 2013-08-06 at 09:29 +0200, Mike Galbraith wrote: > On Tue, 2013-07-30 at 11:35 +0200, Peter Zijlstra wrote: > > > It would be good if you could do what Thomas suggested and look at which > > timer is actually active during your workload. > > Rebuilding regression test trees, some pipe-test results... > > I'm missing mwait_idle() rather a lot on Q6600, and at 3.8, E5620 took a > severe NOHZ drubbing from the menu governor. > > pipe-test, scheduling cross core > > NOTE: nohz is throttled here (patchlet below), as to not eat horrible > microidle cost, see E5620 v3.7.10-nothrottle below. > > Q6600 > v3.8.13 500.6 KHz 1.000 > v3.9.11 422.4 KHz .843 > v3.10.4 420.2 KHz .839 > v3.11-rc3-4-g36f571e 404.7 KHz .808 > > Q6600 3.9 regression: > guilty party is 69fb3676 x86 idle: remove mwait_idle() and "idle=mwait" cmdline param > halt sucks, HTH does one activate mwait_idle_with_hints() [processor_idle()] for core2 boxen? > > E5620 +write 0 -> /dev/cpu_dma_latency, hold open > v3.7.10 578.5 KHz 1.000 675.4 KHz 1.000 > v3.7.10-nothrottle 366.7 KHz .633 395.0 KHz .584 > v3.8.13 468.3 KHz .809 690.0 KHz 1.021 > v3.8.13 idle=mwait 595.1 KHz 1.028 NA > v3.9.11 462.0 KHz .798 691.1 KHz 1.023 > v3.10.4 419.4 KHz .724 570.8 KHz .845 > v3.11-rc3-4-g36f571e 400.1 KHz .691 538.5 KHz .797 > > E5620 3.8 regression: > guilty party: 69a37bea cpuidle: Quickly notice prediction failure for repeat mode > > > Q6600 (2.4 GHz core2 quad) > v3.11-rc3-4-g36f571e v3.8.13 > 7.97% [k] reschedule_interrupt 8.63% [k] __schedule > 6.27% [k] __schedule 6.07% [k] native_sched_clock > 4.74% [k] native_sched_clock 4.96% [k] system_call > 4.23% [k] _raw_spin_lock_irqsave 4.30% [k] _raw_spin_lock_irqsave > 3.39% [k] system_call 4.06% [k] resched_task > 2.89% [k] sched_clock_local 3.44% [k] sched_clock_local > 2.79% [k] mutex_lock 3.39% [k] pipe_read > 2.57% [k] pipe_read 3.21% [k] mutex_lock > 2.55% [k] __switch_to 2.98% [k] read_tsc > 2.24% [k] read_tsc 2.87% [k] __switch_to > > > E5620 (2.4 GHz Westmere quad) > v3.7.10 v3.7.10-nothrottle v3.7.10-nothrottle > 8.01% [k] __schedule 25.80% [k] _raw_spin_unlock_irqrestore 21.80% [k] _raw_spin_unlock_irqrestore > 4.49% [k] resched_tas 4.64% [k] __hrtimer_start_range_ns - _raw_spin_unlock_irqrestore > 3.94% [k] mutex_lock 4.62% [k] timerqueue_add + 37.94% __hrtimer_start_range_ns > 3.44% [k] __switch_to 4.54% [k] __schedule 19.69% hrtimer_cancel > 3.18% [k] menu_select 2.84% [k] enqueue_hrtimer tick_nohz_restart > 3.05% [k] copy_user_generic_string 2.64% [k] resched_task tick_nohz_idle_exit > 3.02% [k] task_waking_fair 2.29% [k] _raw_spin_lock_irqsave cpu_idle > 2.91% [k] mutex_unlock 2.28% [k] mutex_lock start_secondary > 2.82% [k] pipe_read 1.96% [k] __switch_to + 16.05% hrtimer_start_range_ns > 2.32% [k] ktime_get_real 1.73% [k] menu_select 15.46% hrtimer_start > tick_nohz_stop_sched_tick > __tick_nohz_idle_enter > tick_nohz_idle_enter > cpu_idle > start_secondary > 6.37% hrtimer_try_to_cancel > hrtimer_cancel > tick_nohz_restart > tick_nohz_idle_exit > cpu_idle > start_secondary > > v3.8.13 v3.8.13 idle=mwait v3.8.13 (throttled, but menu gov bites.. HARD) > 23.16% [k] _raw_spin_unlock_irqrestore 8.35% [k] __schedule - 22.91% [k] _raw_spin_unlock_irqrestore > 4.93% [k] __schedule 6.49% [k] __switch_to - _raw_spin_unlock_irqrestore > 3.42% [k] resched_task 5.71% [k] resched_task - 47.26% hrtimer_try_to_cancel > 3.27% [k] __switch_to 4.64% [k] mutex_lock hrtimer_cancel > 3.05% [k] mutex_lock 3.48% [k] copy_user_generic_string menu_hrtimer_cancel > 2.32% [k] copy_user_generic_string 3.15% [k] task_waking_fair tick_nohz_idle_exit > 2.30% [k] _raw_spin_lock_irqsave 3.13% [k] pipe_read cpu_idle > 2.15% [k] pipe_read 2.61% [k] mutex_unlock start_secondary > 2.15% [k] task_waking_fair 2.54% [k] finish_task_switch - 40.01% __hrtimer_start_range_ns > 2.08% [k] ktime_get 2.29% [k] _raw_spin_lock_irqsave hrtimer_start > 1.87% [k] mutex_unlock 1.91% [k] idle_cpu menu_select > 1.76% [k] finish_task_switch 1.84% [k] __wake_up_common cpuidle_idle_call > cpu_idle > start_secondary > > v3.9.11 > 18.67% [k] _raw_spin_unlock_irqrestore > 4.36% [k] __schedule > 3.66% [k] __switch_to > 3.13% [k] mutex_lock > 2.97% [k] __hrtimer_start_range_ns > 2.69% [k] _raw_spin_lock_irqsave > 2.38% [k] copy_user_generic_string > 2.34% [k] hrtimer_reprogram.isra.32 > 2.34% [k] task_waking_fair > 2.25% [k] ktime_get > 2.14% [k] pipe_read > 1.98% [k] menu_select > > v3.10.4 > 20.42% [k] _raw_spin_unlock_irqrestore > 4.75% [k] __schedule > 4.42% [k] reschedule_interrupt <== appears in 3.10, guilty party as yet unknown > 3.52% [k] __switch_to > 3.27% [k] resched_task > 2.64% [k] cpuidle_enter_state > 2.63% [k] _raw_spin_lock_irqsave > 2.04% [k] copy_user_generic_string > 2.00% [k] cpu_idle_loop > 1.97% [k] mutex_lock > 1.90% [k] ktime_get > 1.75% [k] task_waking_fair > > v3.11-rc3-4-g36f571e > 18.96% [k] _raw_spin_unlock_irqrestore > 4.84% [k] __schedule > 4.69% [k] reschedule_interrupt > 3.75% [k] __switch_to > 2.62% [k] _raw_spin_lock_irqsave > 2.43% [k] cpuidle_enter_state > 2.28% [k] resched_task > 2.20% [k] cpu_idle_loop > 1.97% [k] copy_user_generic_string > 1.88% [k] ktime_get > 1.81% [k] task_waking_fair > 1.75% [k] mutex_lock > > sched: ratelimit nohz > > Entering nohz code on every micro-idle is too expensive to bear. > > Signed-off-by: Mike Galbraith > > --- > include/linux/sched.h | 5 +++++ > kernel/sched/core.c | 5 +++++ > kernel/time/tick-sched.c | 2 +- > 3 files changed, 11 insertions(+), 1 deletion(-) > > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -235,9 +235,14 @@ extern int runqueue_is_locked(int cpu); > extern void nohz_balance_enter_idle(int cpu); > extern void set_cpu_sd_state_idle(void); > extern int get_nohz_timer_target(void); > +extern int sched_needs_cpu(int cpu); > #else > static inline void nohz_balance_enter_idle(int cpu) { } > static inline void set_cpu_sd_state_idle(void) { } > +static inline int sched_needs_cpu(int cpu) > +{ > + return 0; > +} > #endif > > /* > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -650,6 +650,11 @@ static inline bool got_nohz_idle_kick(vo > return false; > } > > +int sched_needs_cpu(int cpu) > +{ > + return cpu_rq(cpu)->avg_idle < sysctl_sched_migration_cost; > +} > + > #else /* CONFIG_NO_HZ_COMMON */ > > static inline bool got_nohz_idle_kick(void) > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -548,7 +548,7 @@ static ktime_t tick_nohz_stop_sched_tick > time_delta = timekeeping_max_deferment(); > } while (read_seqretry(&jiffies_lock, seq)); > > - if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || > + if (sched_needs_cpu(cpu) || rcu_needs_cpu(cpu, &rcu_delta_jiffies) || > arch_needs_cpu(cpu) || irq_work_needs_cpu()) { > next_jiffies = last_jiffies + 1; > delta_jiffies = 1; > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/