From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Rakib Mullick <rakib.mullick@gmail.com>
Cc: mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/stats: Keep legacy array expiration field to zero.
Date: Mon, 23 Jan 2012 13:56:33 +0100 [thread overview]
Message-ID: <1327323393.2446.9.camel@twins> (raw)
In-Reply-To: <1326991042.6107.4.camel@localhost.localdomain>
On Thu, 2012-01-19 at 22:37 +0600, Rakib Mullick wrote:
> A patch (https://lkml.org/lkml/2012/1/12/224) was sent previously to
> update scheduler stat documentation to address array expiration
> field's use. Then Ingo suggest that, we should also make sure that
> we're exporting a value of zero. So, this patch does those
> accordingly.
This is not a valid changelog
>
> Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
> ---
>
> 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/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);
>
>
This leaves sched_switch completely unused:
# git grep -e "\<sched_switch\>" kernel/sched/
kernel/sched/debug.c: P(sched_switch);
kernel/sched/sched.h: unsigned int sched_switch;
kernel/sched/stats.c: rq->sched_switch, rq->sched_count, rq->sched_goidle,
Best kill that too
next prev parent reply other threads:[~2012-01-23 12:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-19 16:37 [PATCH] sched/stats: Keep legacy array expiration field to zero Rakib Mullick
2012-01-23 12:56 ` Peter Zijlstra [this message]
2012-01-23 16:21 ` Rakib Mullick
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