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From: Noah Goldstein <goldstein.w.n@gmail.com>
To: Eric Dumazet <edumazet@google.com>
Cc: tglx@linutronix.de, mingo@redhat.com,
	Borislav Petkov <bp@alien8.de>,
	dave.hansen@linux.intel.com, X86 ML <x86@kernel.org>,
	hpa@zytor.com, peterz@infradead.org, alexanderduyck@fb.com,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] x86/lib: Optimize 8x loop and memory clobbers in csum_partial.c
Date: Sat, 27 Nov 2021 00:38:58 -0600	[thread overview]
Message-ID: <CAFUsyfJVM_RO5Fy2PyerxiQipz+Nw4oXc0-gm9rR59AHpmqw8Q@mail.gmail.com> (raw)
In-Reply-To: <CANn89iKaTyrNZHCg7i46-db_zudXs0V-BvmwM-5fYLZT2yQr4Q@mail.gmail.com>

On Sat, Nov 27, 2021 at 12:03 AM Eric Dumazet <edumazet@google.com> wrote:
>
> On Fri, Nov 26, 2021 at 8:25 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > Modify the 8x loop to that it uses two independent
> > accumulators. Despite adding more instructions the latency and
> > throughput of the loop is improved because the `adc` chains can now
> > take advantage of multiple execution units.
> >
> > Make the memory clobbers more precise. 'buff' is read only and we know
> > the exact usage range. There is no reason to write-clobber all memory.
> >
> > Relative performance changes on Tigerlake:
> >
> > Time Unit: Ref Cycles
> > Size Unit: Bytes
> >
> > size, lat old, lat new,    tput old,    tput new
> >    0,   4.961,   4.901,       4.887,       4.951
> >    8,   5.590,   5.620,       4.227,       4.252
> >   16,   6.182,   6.202,       4.233,       4.278
> >   24,   7.392,   7.380,       4.256,       4.279
> >   32,   7.371,   7.390,       4.550,       4.537
> >   40,   8.621,   8.601,       4.862,       4.836
> >   48,   9.406,   9.374,       5.206,       5.234
> >   56,  10.535,  10.522,       5.416,       5.447
> >   64,  10.000,   7.590,       6.946,       6.989
> >  100,  14.218,  12.476,       9.429,       9.441
> >  200,  22.115,  16.937,      13.088,      12.852
> >  300,  31.826,  24.640,      19.383,      18.230
> >  400,  39.016,  28.133,      23.223,      21.304
> >  500,  48.815,  36.186,      30.331,      27.104
> >  600,  56.732,  40.120,      35.899,      30.363
> >  700,  66.623,  48.178,      43.044,      36.400
> >  800,  73.259,  51.171,      48.564,      39.173
> >  900,  82.821,  56.635,      58.592,      45.162
> > 1000,  90.780,  63.703,      65.658,      48.718
> >
> > Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
> >
> > tmp
>
> SGTM (not sure what this 'tmp' string means here :) )
>
> Reviewed-by: Eric Dumazet <edumazet@google.com>

Poor rebasing practices :/

Fixed in V3 (only change).

  reply	other threads:[~2021-11-27  6:41 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-25 19:38 [PATCH v1] x86/lib: Optimize 8x loop and memory clobbers in csum_partial.c Noah Goldstein
2021-11-26  1:50 ` Eric Dumazet
2021-11-26  2:15   ` Noah Goldstein
2021-11-26  2:18     ` Noah Goldstein
2021-11-26  2:38       ` Noah Goldstein
2021-11-28 19:47         ` David Laight
2021-11-28 20:59           ` Noah Goldstein
2021-11-28 22:41             ` David Laight
2021-12-02 14:24             ` David Laight
2021-12-02 15:01               ` Eric Dumazet
2021-12-02 20:19                 ` Noah Goldstein
2021-12-02 21:11                   ` David Laight
2021-11-26 16:08     ` Eric Dumazet
2021-11-26 18:17       ` Noah Goldstein
2021-11-26 18:27         ` Eric Dumazet
2021-11-26 18:50           ` Noah Goldstein
2021-11-26 19:14             ` Noah Goldstein
2021-11-26 19:21               ` Eric Dumazet
2021-11-26 19:50                 ` Noah Goldstein
2021-11-26 20:07                   ` Eric Dumazet
2021-11-26 20:33                     ` Noah Goldstein
2021-11-27  0:15                       ` Eric Dumazet
2021-11-27  0:39                         ` Noah Goldstein
2021-11-26 18:17       ` Eric Dumazet
2021-11-27  4:25 ` [PATCH v2] " Noah Goldstein
2021-11-27  6:03   ` Eric Dumazet
2021-11-27  6:38     ` Noah Goldstein [this message]
2021-11-27  6:39 ` [PATCH v3] " Noah Goldstein
2021-11-27  6:51   ` Eric Dumazet
2021-11-27  7:18     ` Noah Goldstein

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