Re: [PATCH v6 1/3] x86/fpu: Measure the Latency of XSAVES and XRSTORS

From: Ingo Molnar
Date: Wed Sep 06 2023 - 18:03:07 EST



* Dave Hansen <dave.hansen@xxxxxxxxx> wrote:

> On 9/6/23 02:18, Yi Sun wrote:
> > Or just use PT
>
> I'd really like to be able to use this mechanism across a wide range of
> systems over time and vendors. For instance, if Intel's AVX512 XSAVE
> implementation is much faster than AMD's, it would be nice to show some
> apples-to-apples data to motivate AMD to do better. We can't do that
> with PT.

Ack - and with the explicit tooling support, it's also very easy to provide
such numbers.

As long as the regular FPU code paths do not get new tracing overhead
added, this looks like a useful tool.

Thanks,

Ingo