From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757706Ab0JRT1R (ORCPT ); Mon, 18 Oct 2010 15:27:17 -0400 Received: from hera.kernel.org ([140.211.167.34]:58859 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757488Ab0JRT1P (ORCPT ); Mon, 18 Oct 2010 15:27:15 -0400 Date: Mon, 18 Oct 2010 19:26:50 GMT From: tip-bot for Venkatesh Pallipadi Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu, venki@google.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, venki@google.com, mingo@elte.hu In-Reply-To: <1286237003-12406-8-git-send-email-venki@google.com> References: <1286237003-12406-8-git-send-email-venki@google.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched: Remove irq time from available CPU power Message-ID: Git-Commit-ID: aa483808516ca5cacfa0e5849691f64fec25828e X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Mon, 18 Oct 2010 19:26:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: aa483808516ca5cacfa0e5849691f64fec25828e Gitweb: http://git.kernel.org/tip/aa483808516ca5cacfa0e5849691f64fec25828e Author: Venkatesh Pallipadi AuthorDate: Mon, 4 Oct 2010 17:03:22 -0700 Committer: Ingo Molnar CommitDate: Mon, 18 Oct 2010 20:52:27 +0200 sched: Remove irq time from available CPU power The idea was suggested by Peter Zijlstra here: http://marc.info/?l=linux-kernel&m=127476934517534&w=2 irq time is technically not available to the tasks running on the CPU. This patch removes irq time from CPU power piggybacking on sched_rt_avg_update(). Tested this by keeping CPU X busy with a network intensive task having 75% oa a single CPU irq processing (hard+soft) on a 4-way system. And start seven cycle soakers on the system. Without this change, there will be two tasks on each CPU. With this change, there is a single task on irq busy CPU X and remaining 7 tasks are spread around among other 3 CPUs. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Peter Zijlstra LKML-Reference: <1286237003-12406-8-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 18 ++++++++++++++++++ kernel/sched_fair.c | 8 +++++++- kernel/sched_features.h | 5 +++++ 3 files changed, 30 insertions(+), 1 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 9e01b71..bff9ef5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -519,6 +519,10 @@ struct rq { u64 avg_idle; #endif +#ifdef CONFIG_IRQ_TIME_ACCOUNTING + u64 prev_irq_time; +#endif + /* calc_load related fields */ unsigned long calc_load_update; long calc_load_active; @@ -643,6 +647,7 @@ static inline struct task_group *task_group(struct task_struct *p) #endif /* CONFIG_CGROUP_SCHED */ static u64 irq_time_cpu(int cpu); +static void sched_irq_time_avg_update(struct rq *rq, u64 irq_time); inline void update_rq_clock(struct rq *rq) { @@ -654,6 +659,8 @@ inline void update_rq_clock(struct rq *rq) irq_time = irq_time_cpu(cpu); if (rq->clock - irq_time > rq->clock_task) rq->clock_task = rq->clock - irq_time; + + sched_irq_time_avg_update(rq, irq_time); } } @@ -1985,6 +1992,15 @@ void account_system_vtime(struct task_struct *curr) local_irq_restore(flags); } +static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time) +{ + if (sched_clock_irqtime && sched_feat(NONIRQ_POWER)) { + u64 delta_irq = curr_irq_time - rq->prev_irq_time; + rq->prev_irq_time = curr_irq_time; + sched_rt_avg_update(rq, delta_irq); + } +} + #else static u64 irq_time_cpu(int cpu) @@ -1992,6 +2008,8 @@ static u64 irq_time_cpu(int cpu) return 0; } +static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time) { } + #endif #include "sched_idletask.c" diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index c358d40..74cccfa 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2275,7 +2275,13 @@ unsigned long scale_rt_power(int cpu) u64 total, available; total = sched_avg_period() + (rq->clock - rq->age_stamp); - available = total - rq->rt_avg; + + if (unlikely(total < rq->rt_avg)) { + /* Ensures that power won't end up being negative */ + available = 0; + } else { + available = total - rq->rt_avg; + } if (unlikely((s64)total < SCHED_LOAD_SCALE)) total = SCHED_LOAD_SCALE; diff --git a/kernel/sched_features.h b/kernel/sched_features.h index 83c66e8..185f920 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -61,3 +61,8 @@ SCHED_FEAT(ASYM_EFF_LOAD, 1) * release the lock. Decreases scheduling overhead. */ SCHED_FEAT(OWNER_SPIN, 1) + +/* + * Decrement CPU power based on irq activity + */ +SCHED_FEAT(NONIRQ_POWER, 1)