linux-kernel - Re: [PATCH v1] x86/lib: Optimize 8x loop and memory clobbers in csum

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Message-ID: <CANn89iJb_2666U4qgrqsjqEyT9_rA9SKRThbdy_--4_X8rFMYg@mail.gmail.com>
Date:   Fri, 26 Nov 2021 16:15:05 -0800
From:   Eric Dumazet <edumazet@...gle.com>
To:     Noah Goldstein <goldstein.w.n@...il.com>
Cc:     tglx@...utronix.de, mingo@...hat.com,
        Borislav Petkov <bp@...en8.de>, dave.hansen@...ux.intel.com,
        X86 ML <x86@...nel.org>, hpa@...or.com, peterz@...radead.org,
        alexanderduyck@...com, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] x86/lib: Optimize 8x loop and memory clobbers in csum_partial.c

On Fri, Nov 26, 2021 at 12:33 PM Noah Goldstein <goldstein.w.n@...il.com> wrote:
>
> On Fri, Nov 26, 2021 at 2:07 PM Eric Dumazet <edumazet@...gle.com> wrote:
> >
> > On Fri, Nov 26, 2021 at 11:50 AM Noah Goldstein <goldstein.w.n@...il.com> wrote:
> > >
> > > Bright :) but it will need a BMI support check.
> >
> > Yes, probably not worth the pain.
>
> Making a V2 for my patch with your optimization for the loop case. Do you think
> 1 or 2 accum for the 32 byte case?
>

I would vote for something simpler, thus one accum, since this 32byte
block is only run one time ?

Thanks !