From: Dave Jones <davej@redhat.com>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: linux-kernel@vger.kernel.org, sebastien.dugue@bull.net,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Subject: Re: [PATCH v2 2/2] x86: add prefetching to do_csum
Date: Wed, 6 Nov 2013 10:34:29 -0500 [thread overview]
Message-ID: <20131106153429.GA26336@redhat.com> (raw)
In-Reply-To: <1383751399-10298-3-git-send-email-nhorman@tuxdriver.com>
On Wed, Nov 06, 2013 at 10:23:19AM -0500, Neil Horman wrote:
> do_csum was identified via perf recently as a hot spot when doing
> receive on ip over infiniband workloads. After alot of testing and
> ideas, we found the best optimization available to us currently is to
> prefetch the entire data buffer prior to doing the checksum
>
> diff --git a/arch/x86/lib/csum-partial_64.c b/arch/x86/lib/csum-partial_64.c
> index 9845371..9f2d3ee 100644
> --- a/arch/x86/lib/csum-partial_64.c
> +++ b/arch/x86/lib/csum-partial_64.c
> @@ -29,8 +29,15 @@ static inline unsigned short from32to16(unsigned a)
> * Things tried and found to not make it faster:
> * Manual Prefetching
> * Unrolling to an 128 bytes inner loop.
> - * Using interleaving with more registers to break the carry chains.
Did you mean perhaps to remove the "Manual Prefetching" line instead ?
(Curious, what was tried before that made it not worthwhile?)
Dave
next prev parent reply other threads:[~2013-11-06 15:34 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-11 16:51 [PATCH] x86: Run checksumming in parallel accross multiple alu's Neil Horman
2013-10-12 17:21 ` Ingo Molnar
2013-10-13 12:53 ` Neil Horman
2013-10-14 20:28 ` Neil Horman
2013-10-14 21:19 ` Eric Dumazet
2013-10-14 22:18 ` Eric Dumazet
2013-10-14 22:37 ` Joe Perches
2013-10-14 22:44 ` Eric Dumazet
2013-10-14 22:49 ` Joe Perches
2013-10-15 7:41 ` Ingo Molnar
2013-10-15 10:51 ` Borislav Petkov
2013-10-15 12:04 ` Ingo Molnar
2013-10-15 16:21 ` Joe Perches
2013-10-16 0:34 ` Eric Dumazet
2013-10-16 6:25 ` Ingo Molnar
2013-10-16 16:55 ` Joe Perches
2013-10-17 0:34 ` Neil Horman
2013-10-17 1:42 ` Eric Dumazet
2013-10-18 16:50 ` Neil Horman
2013-10-18 17:20 ` Eric Dumazet
2013-10-18 20:11 ` Neil Horman
2013-10-18 21:15 ` Eric Dumazet
2013-10-20 21:29 ` Neil Horman
2013-10-21 17:31 ` Eric Dumazet
2013-10-21 17:46 ` Neil Horman
2013-10-21 19:21 ` Neil Horman
2013-10-21 19:44 ` Eric Dumazet
2013-10-21 20:19 ` Neil Horman
2013-10-26 12:01 ` Ingo Molnar
2013-10-26 13:58 ` Neil Horman
2013-10-27 7:26 ` Ingo Molnar
2013-10-27 17:05 ` Neil Horman
2013-10-17 8:41 ` Ingo Molnar
2013-10-17 18:19 ` H. Peter Anvin
2013-10-17 18:48 ` Eric Dumazet
2013-10-18 6:43 ` Ingo Molnar
2013-10-28 16:01 ` Neil Horman
2013-10-28 16:20 ` Ingo Molnar
2013-10-28 17:49 ` Neil Horman
2013-10-28 16:24 ` Ingo Molnar
2013-10-28 16:49 ` David Ahern
2013-10-28 17:46 ` Neil Horman
2013-10-28 18:29 ` Neil Horman
2013-10-29 8:25 ` Ingo Molnar
2013-10-29 11:20 ` Neil Horman
2013-10-29 11:30 ` Ingo Molnar
2013-10-29 11:49 ` Neil Horman
2013-10-29 12:52 ` Ingo Molnar
2013-10-29 13:07 ` Neil Horman
2013-10-29 13:11 ` Ingo Molnar
2013-10-29 13:20 ` Neil Horman
2013-10-29 14:17 ` Neil Horman
2013-10-29 14:27 ` Ingo Molnar
2013-10-29 20:26 ` Neil Horman
2013-10-31 10:22 ` Ingo Molnar
2013-10-31 14:33 ` Neil Horman
2013-11-01 9:13 ` Ingo Molnar
2013-11-01 14:06 ` Neil Horman
2013-10-29 14:12 ` David Ahern
2013-10-15 7:32 ` Ingo Molnar
2013-10-15 13:14 ` Neil Horman
2013-10-12 22:29 ` H. Peter Anvin
2013-10-13 12:53 ` Neil Horman
2013-10-18 16:42 ` Neil Horman
2013-10-18 17:09 ` H. Peter Anvin
2013-10-25 13:06 ` Neil Horman
2013-10-14 4:38 ` Andi Kleen
2013-10-14 7:49 ` Ingo Molnar
2013-10-14 21:07 ` Eric Dumazet
2013-10-15 13:17 ` Neil Horman
2013-10-14 20:25 ` Neil Horman
2013-10-15 7:12 ` Sébastien Dugué
2013-10-15 13:33 ` Andi Kleen
2013-10-15 13:56 ` Sébastien Dugué
2013-10-15 14:06 ` Eric Dumazet
2013-10-15 14:15 ` Sébastien Dugué
2013-10-15 14:26 ` Eric Dumazet
2013-10-15 14:52 ` Eric Dumazet
2013-10-15 16:02 ` Andi Kleen
2013-10-16 0:28 ` Eric Dumazet
2013-11-06 15:23 ` x86: Enhance perf checksum profiling and x86 implementation Neil Horman
2013-11-06 15:23 ` [PATCH v2 1/2] perf: Add csum benchmark tests to perf Neil Horman
2013-11-06 15:23 ` [PATCH v2 2/2] x86: add prefetching to do_csum Neil Horman
2013-11-06 15:34 ` Dave Jones [this message]
2013-11-06 15:54 ` Neil Horman
2013-11-06 17:19 ` Joe Perches
2013-11-06 18:11 ` Neil Horman
2013-11-06 20:02 ` Neil Horman
2013-11-06 20:07 ` Joe Perches
2013-11-08 16:25 ` Neil Horman
2013-11-08 16:51 ` Joe Perches
2013-11-08 19:07 ` Neil Horman
2013-11-08 19:17 ` Joe Perches
2013-11-08 20:08 ` Neil Horman
2013-11-08 19:17 ` H. Peter Anvin
2013-11-08 19:01 ` Neil Horman
2013-11-08 19:33 ` Joe Perches
2013-11-08 20:14 ` Neil Horman
2013-11-08 20:29 ` Joe Perches
2013-11-11 19:40 ` Neil Horman
2013-11-11 21:18 ` Ingo Molnar
2013-11-06 18:23 ` Eric Dumazet
2013-11-06 18:59 ` Neil Horman
2013-11-06 20:19 ` Andi Kleen
2013-11-07 21:23 ` Neil Horman
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