Re: [PATCH] Lazy FPU for SVM

Anthony Liguori
2007-04-24T13:59:46Z

Avi Kivity wrote:
> Anthony Liguori wrote:
>
> [updated patch]
>
> Applied.
>
>
>> Hard to say exactly because of the noise. I did two runs of 4
>> test/vmexit:
>>
>> Before 4091, 4194, 4559, 4439
>> After: 3979, 4324, 3918, 3910
>>
>> So there's definitely a speedup, but probably only 100-200 cycles.
>>
>>
>
> Running on an idle, headless server with the vcpu pinned reduces
> variability to a few cycles in the after case. Strangely, the
> variability is high in the before case. I get a similar disappointing
> result of 100-200 cycles.
>

I previously measured how long fx_save/fx_restore took and it was right
around 150 cycles on AMD.

Regards,

Anthony Liguori