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

Peter Zijlstra
2010-10-15T14:38:52Z

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.