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

H. Peter Anvin
2012-03-26T22:47:59Z

On 03/26/2012 03:47 PM, Suresh Siddha wrote:
> 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.
>

Nice.

-hpa