From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755740Ab2AXQhV (ORCPT ); Tue, 24 Jan 2012 11:37:21 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:63859 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755691Ab2AXQhR (ORCPT ); Tue, 24 Jan 2012 11:37:17 -0500 Subject: [PATCH] sched: Remove sched_switch completely from runqueue structure. From: Rakib Mullick To: mingo@elte.hu, a.p.zijlstra@chello.nl Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Date: Tue, 24 Jan 2012 22:33:56 +0600 Message-ID: <1327422836.27181.5.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 (2.32.1-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently we don't utilize sched_switch field properly for counting context switch numbers. We can remove it. But, simply removing sched_switch field from sched_stat output will break ABI integrity. So, we make sure /proc/sched_stat output remains as it is by hardcoding zero in place of sched_switch field's output and remove sched_switch from sched_debug output too. And update scheduler-stat documentation accordingly. Signed-off-by: Rakib Mullick --- diff --git a/Documentation/scheduler/sched-stats.txt b/Documentation/scheduler/sched-stats.txt index 1cd5d51..8259b34 100644 --- a/Documentation/scheduler/sched-stats.txt +++ b/Documentation/scheduler/sched-stats.txt @@ -38,7 +38,8 @@ First field is a sched_yield() statistic: 1) # of times sched_yield() was called Next three are schedule() statistics: - 2) # of times we switched to the expired queue and reused it + 2) This field is a legacy array expiration count field used in the O(1) + scheduler. We kept it for ABI compatibility, but it is always set to zero. 3) # of times schedule() was called 4) # of times schedule() left the processor idle diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 2a075e1..09acaa1 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -288,7 +288,6 @@ static void print_cpu(struct seq_file *m, int cpu) P(yld_count); - P(sched_switch); P(sched_count); P(sched_goidle); #ifdef CONFIG_SMP diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 98c0c26..8a2c768 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -462,7 +462,6 @@ struct rq { unsigned int yld_count; /* schedule() stats */ - unsigned int sched_switch; unsigned int sched_count; unsigned int sched_goidle; diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c index 2a581ba..903ffa9e 100644 --- a/kernel/sched/stats.c +++ b/kernel/sched/stats.c @@ -32,9 +32,9 @@ static int show_schedstat(struct seq_file *seq, void *v) /* runqueue-specific stats */ seq_printf(seq, - "cpu%d %u %u %u %u %u %u %llu %llu %lu", + "cpu%d %u 0 %u %u %u %u %llu %llu %lu", cpu, rq->yld_count, - rq->sched_switch, rq->sched_count, rq->sched_goidle, + rq->sched_count, rq->sched_goidle, rq->ttwu_count, rq->ttwu_local, rq->rq_cpu_time, rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);