Re: [PATCH] x86/fpu: don't set TIF_NEED_FPU_LOAD for PF_IO_WORKER threads

[Peter Zijlstra]

On Tue, Jan 24, 2023 at 08:23:20AM -0700, Jens Axboe wrote:
> We don't set it on PF_KTHREAD threads as they never return to userspace,
> and PF_IO_WORKER threads are identical in that regard. As they keep
> running in the kernel until they die, skip setting the FPU flag on them.

No objection to the actual patch; but this changelog fails to tell us
why this is important.

What made you get up and write this patch :-) Presumably this is a
performance issue? If so, can you quantify how much?