Re: [RFC v1 2/2] mm: SLUB Freelist randomization

From: Thomas Garnier
Date: Wed May 18 2016 - 14:35:06 EST


Yes, I agree that it is not related to the changes.

On Wed, May 18, 2016 at 11:24 AM, Christoph Lameter <cl@xxxxxxxxx> wrote:
> 0.On Wed, 18 May 2016, Thomas Garnier wrote:
>
>> slab_test, before:
>> 10000 times kmalloc(8) -> 67 cycles kfree -> 101 cycles
>> 10000 times kmalloc(16) -> 68 cycles kfree -> 109 cycles
>> 10000 times kmalloc(32) -> 76 cycles kfree -> 119 cycles
>> 10000 times kmalloc(64) -> 88 cycles kfree -> 114 cycles
>
>> After:
>> 10000 times kmalloc(8) -> 60 cycles kfree -> 74 cycles
>> 10000 times kmalloc(16) -> 63 cycles kfree -> 78 cycles
>> 10000 times kmalloc(32) -> 72 cycles kfree -> 85 cycles
>> 10000 times kmalloc(64) -> 91 cycles kfree -> 99 cycles
>
> Erm... The fastpath was not touched and the tests primarily exercise the
> fastpath. This is likely some artifact of code placement by the compiler?
>