From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755801AbZEKMeU (ORCPT ); Mon, 11 May 2009 08:34:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753058AbZEKMeJ (ORCPT ); Mon, 11 May 2009 08:34:09 -0400 Received: from hera.kernel.org ([140.211.167.34]:39599 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753245AbZEKMeI (ORCPT ); Mon, 11 May 2009 08:34:08 -0400 Date: Mon, 11 May 2009 12:33:28 GMT From: tip-bot for KOSAKI Motohiro To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, schwidefsky@de.ibm.com, dhaval@linux.vnet.ibm.com, balajirrao@gmail.com, balbir@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com, tglx@linutronix.de, kamezawa.hiroyu@jp.fujitsu.com, kosaki.motohiro@jp.fujitsu.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, schwidefsky@de.ibm.com, balajirrao@gmail.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com, tglx@linutronix.de, kosaki.motohiro@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, mingo@elte.hu In-Reply-To: <20090509191430.3AD5.A69D9226@jp.fujitsu.com> References: <20090509191430.3AD5.A69D9226@jp.fujitsu.com> Subject: [tip:sched/core] sched: cpuacct: Use bigger percpu counter batch values for stats counters Message-ID: Git-Commit-ID: 0719318fea31d54d13ed8ead7f4a277038bd75a2 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-4.0 (hera.kernel.org [127.0.0.1]); Mon, 11 May 2009 12:33:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 0719318fea31d54d13ed8ead7f4a277038bd75a2 Gitweb: http://git.kernel.org/tip/0719318fea31d54d13ed8ead7f4a277038bd75a2 Author: KOSAKI Motohiro AuthorDate: Sat, 9 May 2009 19:14:58 +0900 Committer: Ingo Molnar CommitDate: Mon, 11 May 2009 14:21:32 +0200 sched: cpuacct: Use bigger percpu counter batch values for stats counters percpu counters used to accumulate statistics in cpuacct controller use the default batch value [max(2*nr_cpus, 32)] which can be too small for archs that define VIRT_CPU_ACCOUNTING. In such archs, a tick could result in cputime updates in the range of thousands. As a result, cpuacct_update_stats() would end up acquiring the percpu counter spinlock on every tick which is not good for performance. Let those architectures to have a bigger batch threshold so that percpu counter spinlock isn't taken on every tick. This change doesn't affect the archs which don't define VIRT_CPU_ACCOUNTING and they continue to have the default percpu counter batch value. v5: - move cpuacct_batch initialization into sched_init() v4: - rewrite patch description (thanks Bharata!) - append read_mostly to cpuacct_batch - cpuacct_batch is initialized by sched_init_debug() v3: - revert using percpu_counter_sum() v2: - use percpu_counter_sum() instead percpu_counter_read() Signed-off-by: Bharata B Rao Signed-off-by: KOSAKI Motohiro Acked-by: Peter Zijlstra Cc: Balaji Rao Cc: Dhaval Giani Cc: KAMEZAWA Hiroyuki Cc: Balbir Singh Cc: Martin Schwidefsky Cc: KOSAKI Motohiro LKML-Reference: <20090509191430.3AD5.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 8908d19..beadb82 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -872,6 +872,8 @@ static __read_mostly int scheduler_running; */ int sysctl_sched_rt_runtime = 950000; +static __read_mostly s32 cpuacct_batch; + static inline u64 global_rt_period(void) { return (u64)sysctl_sched_rt_period * NSEC_PER_USEC; @@ -9181,6 +9183,8 @@ void __init sched_init(void) alloc_bootmem_cpumask_var(&cpu_isolated_map); #endif /* SMP */ + cpuacct_batch = jiffies_to_cputime(percpu_counter_batch); + scheduler_running = 1; } @@ -10354,7 +10358,8 @@ static void cpuacct_update_stats(struct task_struct *tsk, ca = task_ca(tsk); do { - percpu_counter_add(&ca->cpustat[idx], val); + __percpu_counter_add(&ca->cpustat[idx], val, cpuacct_batch); + ca = ca->parent; } while (ca); rcu_read_unlock();