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* [PATCH] Optimise tick_nohz_stop_sched_tick() a bit
@ 2008-02-28 14:10 Karsten Wiese
2008-02-29 1:16 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Karsten Wiese @ 2008-02-28 14:10 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Thomas Gleixner, Ingo Molnar
Call
ts = &per_cpu(tick_cpu_sched, cpu);
and
cpu = smp_processor_id();
once instead of twice.
No functional change done, as changed code runs with local irq off.
Reduces source lines and text size (20bytes on x86_64).
Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de>
---
kernel/time/tick-sched.c | 6 ++----
1 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 686da82..851a852 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -158,9 +158,8 @@ void tick_nohz_stop_idle(int cpu)
}
}
-static ktime_t tick_nohz_start_idle(int cpu)
+static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
{
- struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now, delta;
now = ktime_get();
@@ -201,8 +200,8 @@ void tick_nohz_stop_sched_tick(void)
local_irq_save(flags);
cpu = smp_processor_id();
- now = tick_nohz_start_idle(cpu);
ts = &per_cpu(tick_cpu_sched, cpu);
+ now = tick_nohz_start_idle(cpu, ts);
/*
* If this cpu is offline and it is the one which updates
@@ -222,7 +221,6 @@ void tick_nohz_stop_sched_tick(void)
if (need_resched())
goto end;
- cpu = smp_processor_id();
if (unlikely(local_softirq_pending())) {
static int ratelimit;
--
1.5.3.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Optimise tick_nohz_stop_sched_tick() a bit
2008-02-28 14:10 [PATCH] Optimise tick_nohz_stop_sched_tick() a bit Karsten Wiese
@ 2008-02-29 1:16 ` Andrew Morton
2008-02-29 15:57 ` Thomas Gleixner
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2008-02-29 1:16 UTC (permalink / raw)
To: Karsten Wiese; +Cc: linux-kernel, Thomas Gleixner, Ingo Molnar
On Thu, 28 Feb 2008 15:10:50 +0100 Karsten Wiese <fzu@wemgehoertderstaat.de> wrote:
>
> Call
> ts = &per_cpu(tick_cpu_sched, cpu);
> and
> cpu = smp_processor_id();
> once instead of twice.
>
> No functional change done, as changed code runs with local irq off.
> Reduces source lines and text size (20bytes on x86_64).
>
> Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de>
> ---
> kernel/time/tick-sched.c | 6 ++----
> 1 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 686da82..851a852 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -158,9 +158,8 @@ void tick_nohz_stop_idle(int cpu)
> }
> }
>
> -static ktime_t tick_nohz_start_idle(int cpu)
> +static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
Argument `cpu' is now unused.
> {
> - struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
> ktime_t now, delta;
>
> now = ktime_get();
> @@ -201,8 +200,8 @@ void tick_nohz_stop_sched_tick(void)
> local_irq_save(flags);
>
> cpu = smp_processor_id();
> - now = tick_nohz_start_idle(cpu);
> ts = &per_cpu(tick_cpu_sched, cpu);
> + now = tick_nohz_start_idle(cpu, ts);
>
> /*
> * If this cpu is offline and it is the one which updates
> @@ -222,7 +221,6 @@ void tick_nohz_stop_sched_tick(void)
> if (need_resched())
> goto end;
>
> - cpu = smp_processor_id();
> if (unlikely(local_softirq_pending())) {
> static int ratelimit;
>
--- a/kernel/time/tick-sched.c~optimise-tick_nohz_stop_sched_tick-a-bit-fix
+++ a/kernel/time/tick-sched.c
@@ -158,7 +158,7 @@ void tick_nohz_stop_idle(int cpu)
}
}
-static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
+static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
{
ktime_t now, delta;
@@ -200,7 +200,7 @@ void tick_nohz_stop_sched_tick(void)
cpu = smp_processor_id();
ts = &per_cpu(tick_cpu_sched, cpu);
- now = tick_nohz_start_idle(cpu, ts);
+ now = tick_nohz_start_idle(ts);
/*
* If this cpu is offline and it is the one which updates
_
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Optimise tick_nohz_stop_sched_tick() a bit
2008-02-29 1:16 ` Andrew Morton
@ 2008-02-29 15:57 ` Thomas Gleixner
0 siblings, 0 replies; 3+ messages in thread
From: Thomas Gleixner @ 2008-02-29 15:57 UTC (permalink / raw)
To: Andrew Morton; +Cc: Karsten Wiese, linux-kernel, Ingo Molnar
On Thu, 28 Feb 2008, Andrew Morton wrote:
> On Thu, 28 Feb 2008 15:10:50 +0100 Karsten Wiese <fzu@wemgehoertderstaat.de> wrote:
> -static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
> +static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
> {
> ktime_t now, delta;
>
> @@ -200,7 +200,7 @@ void tick_nohz_stop_sched_tick(void)
>
> cpu = smp_processor_id();
> ts = &per_cpu(tick_cpu_sched, cpu);
> - now = tick_nohz_start_idle(cpu, ts);
> + now = tick_nohz_start_idle(ts);
>
> /*
> * If this cpu is offline and it is the one which updates
Combined patch applied to hrt.git
Thanks,
tglx
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2008-02-29 15:58 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2008-02-28 14:10 [PATCH] Optimise tick_nohz_stop_sched_tick() a bit Karsten Wiese
2008-02-29 1:16 ` Andrew Morton
2008-02-29 15:57 ` Thomas Gleixner
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