Re: [PATCH] Fix posix-cpu-timer breakage caused by stale p->last_ran value

From: Ingo Molnar
Date: Thu Feb 22 2007 - 02:51:38 EST

* Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> The problem is that the p->last_ran value is not updated after a
> context switch. So a subsequent call to current_sched_time()
> calculates with a stale p->last_ran value, i.e. accounts the full
> time, which the task was scheduled away.
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

> sched_info_switch(prev, next);
> if (likely(prev != next)) {
> - next->timestamp = now;
> + next->timestamp = next->last_ran = now;

ouch! nice catch. Also for v2.6.20.2 i think. 2.6.19 should be

Acked-by: Ingo Molnar <mingo@xxxxxxx>

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