linux-kernel - Re: [PATCH] x86: handle the tail in rep_movs_alternative() with an overlapping store

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Message-ID: <CAHk-=wisCz3HHBKjgHKfnCjNf=fLyr40fWH=D7jYe+EpHnWJeg@mail.gmail.com>
Date: Tue, 25 Mar 2025 15:51:55 -0700
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Herton Krzesinski <hkrzesin@...hat.com>
Cc: David Laight <david.laight.linux@...il.com>, Mateusz Guzik <mjguzik@...il.com>, x86@...nel.org, 
	tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, 
	dave.hansen@...ux.intel.com, hpa@...or.com, olichtne@...hat.com, 
	atomasov@...hat.com, aokuliar@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: handle the tail in rep_movs_alternative() with an
 overlapping store

On Tue, 25 Mar 2025 at 15:42, Herton Krzesinski <hkrzesin@...hat.com> wrote:
>
> I have been trying to also measure the impact of changes like above, however,
> it seems I don't get improvement or it's limited due impact of
> profiling,

In my experience, profiling overhead - assuming you have half-way
modern hardware that has support for it - is simply not an issue.

So I think that if we don't have performance numbers on some hardware
where it can be shown to matter, let's just leave things be.

            Linus