* [PATCH] sched/stats: Keep legacy array expiration field to zero.
@ 2012-01-19 16:37 Rakib Mullick
2012-01-23 12:56 ` Peter Zijlstra
0 siblings, 1 reply; 3+ messages in thread
From: Rakib Mullick @ 2012-01-19 16:37 UTC (permalink / raw)
To: mingo, Peter Zijlstra; +Cc: linux-kernel
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.
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);
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] sched/stats: Keep legacy array expiration field to zero.
2012-01-19 16:37 [PATCH] sched/stats: Keep legacy array expiration field to zero Rakib Mullick
@ 2012-01-23 12:56 ` Peter Zijlstra
2012-01-23 16:21 ` Rakib Mullick
0 siblings, 1 reply; 3+ messages in thread
From: Peter Zijlstra @ 2012-01-23 12:56 UTC (permalink / raw)
To: Rakib Mullick; +Cc: mingo, linux-kernel
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] sched/stats: Keep legacy array expiration field to zero.
2012-01-23 12:56 ` Peter Zijlstra
@ 2012-01-23 16:21 ` Rakib Mullick
0 siblings, 0 replies; 3+ messages in thread
From: Rakib Mullick @ 2012-01-23 16:21 UTC (permalink / raw)
To: Peter Zijlstra; +Cc: mingo, linux-kernel
On Mon, Jan 23, 2012 at 6:56 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> 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
Ok, I'll elaborate the changelog. (Actually, I had my finger crossed :) )
>
> 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
>
I asked on previous posting about removing rq->sched_switch. But
didn't get any specific answer. Anyway, will do it.
Thanks,
Rakib
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-01-19 16:37 [PATCH] sched/stats: Keep legacy array expiration field to zero Rakib Mullick
2012-01-23 12:56 ` Peter Zijlstra
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