Re: [patch] x86, tlb: switch cr3 in leave_mm() only when needed

Suresh Siddha
2012-03-26T22:45:43Z

On Fri, 2012-03-23 at 09:37 +0100, Ingo Molnar wrote:
> * Suresh Siddha <suresh.b.siddha@intel.com> wrote:
>
> > I was reviewing this code in some other context and thought
> > this optimization makes sense. Unless someone beats me, I can
> > collect some data on Monday.
>
> Would be really nice to get this data.
>

On an idle system with 32logical cpu's (2 socket/8-core each) the
original kernel did the unnecessary load_cr3 2988 times during an
interval of 5 seconds.

With the fix, that count drops to 9 times.

thanks,
suresh