* [PATCH] sched: Remove sched_switch completely from runqueue structure.
@ 2012-01-24 16:33 Rakib Mullick
2012-01-25 12:33 ` Peter Zijlstra
2012-01-28 12:08 ` [tip:sched/core] sched: Remove sched_switch tip-bot for Rakib Mullick
0 siblings, 2 replies; 3+ messages in thread
From: Rakib Mullick @ 2012-01-24 16:33 UTC (permalink / raw
To: mingo, a.p.zijlstra; +Cc: linux-kernel
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 <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/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);
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] sched: Remove sched_switch completely from runqueue structure.
2012-01-24 16:33 [PATCH] sched: Remove sched_switch completely from runqueue structure Rakib Mullick
@ 2012-01-25 12:33 ` Peter Zijlstra
2012-01-28 12:08 ` [tip:sched/core] sched: Remove sched_switch tip-bot for Rakib Mullick
1 sibling, 0 replies; 3+ messages in thread
From: Peter Zijlstra @ 2012-01-25 12:33 UTC (permalink / raw
To: Rakib Mullick; +Cc: mingo, linux-kernel
On Tue, 2012-01-24 at 22:33 +0600, Rakib Mullick wrote:
> 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 <rakib.mullick@gmail.com>
Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
* [tip:sched/core] sched: Remove sched_switch
2012-01-24 16:33 [PATCH] sched: Remove sched_switch completely from runqueue structure Rakib Mullick
2012-01-25 12:33 ` Peter Zijlstra
@ 2012-01-28 12:08 ` tip-bot for Rakib Mullick
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Rakib Mullick @ 2012-01-28 12:08 UTC (permalink / raw
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, rakib.mullick, a.p.zijlstra, tglx,
mingo
Commit-ID: 30fd049afcfed50e022704036e8629d6bdfe84e6
Gitweb: http://git.kernel.org/tip/30fd049afcfed50e022704036e8629d6bdfe84e6
Author: Rakib Mullick <rakib.mullick@gmail.com>
AuthorDate: Tue, 24 Jan 2012 22:33:56 +0600
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 27 Jan 2012 13:28:53 +0100
sched: Remove sched_switch
Currently we don't utilize the sched_switch field anymore.
But, simply removing sched_switch field from the middle of the
sched_stat output will break tools.
So, to stay compatible we hardcode it to zero and remove the
field from the scheduler data structures.
Update the schedstat documentation accordingly.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1327422836.27181.5.camel@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
Documentation/scheduler/sched-stats.txt | 3 ++-
kernel/sched/debug.c | 1 -
kernel/sched/sched.h | 1 -
kernel/sched/stats.c | 4 ++--
4 files changed, 4 insertions(+), 5 deletions(-)
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);
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2012-01-24 16:33 [PATCH] sched: Remove sched_switch completely from runqueue structure Rakib Mullick
2012-01-25 12:33 ` Peter Zijlstra
2012-01-28 12:08 ` [tip:sched/core] sched: Remove sched_switch tip-bot for Rakib Mullick
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