Re: [PATCH 5/8] x86: Add IRQ_TIME_ACCOUNTING in x86 -v4

From: Peter Zijlstra
Date: Fri Oct 15 2010 - 10:38:55 EST


On Mon, 2010-10-04 at 17:03 -0700, Venkatesh Pallipadi wrote:
> @@ -801,6 +805,7 @@ void mark_tsc_unstable(char *reason)
> if (!tsc_unstable) {
> tsc_unstable = 1;
> sched_clock_stable = 0;
> + disable_sched_clock_irqtime();
> printk(KERN_INFO "Marking TSC unstable due to %s\n", reason);
> /* Change only the rating, when not registered */
> if (clocksource_tsc.mult)

I think we can be less strict that this and keep it enabled for
everything with constant tsc and nonstop tsc.

Since we're using it strictly per-cpu the cross-cpu sync isn't really
important, all we need it to know the per-cpu value doesn't go all
screwy on us.


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