From: Daniel Borkmann <daniel@iogearbox.net>
To: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
netdev@vger.kernel.org
Cc: linux-sctp@vger.kernel.org, Neil Horman <nhorman@tuxdriver.com>,
Vlad Yasevich <vyasevich@gmail.com>
Subject: Re: [PATCH net] sctp: linearize early if it's not GSO
Date: Tue, 16 Aug 2016 22:59:17 +0000 [thread overview]
Message-ID: <57B39AC5.7000002@iogearbox.net> (raw)
In-Reply-To: <a4bc263e62ced9f5790932f11e7d829c36566808.1471386679.git.marcelo.leitner@gmail.com>
On 08/17/2016 12:35 AM, Marcelo Ricardo Leitner wrote:
> Because otherwise when crc computation is still needed it's way more
> expensive than on a linear buffer to the point that it affects
> performance.
>
> It's so expensive that netperf test gives a perf output as below:
>
> Overhead Shared Object Symbol
> 69,44% [kernel] [k] gf2_matrix_square
> 2,84% [kernel] [k] crc32_generic_combine.part.0
> 2,78% [kernel] [k] _raw_spin_lock_bh
What kernel is this, seems not net kernel?
$ git grep -n gf2_matrix_square
$ git grep -n crc32_generic_combine
$
Maybe RHEL? Did you consider backporting 6d514b4e7737 et al?
> And performance goes from 2Gbit/s to 0.5Gbit/s on this test. Doing the
> linearization before checksumming is enough to restore it.
>
> Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
WARNING: multiple messages have this Message-ID (diff)
From: Daniel Borkmann <daniel@iogearbox.net>
To: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
netdev@vger.kernel.org
Cc: linux-sctp@vger.kernel.org, Neil Horman <nhorman@tuxdriver.com>,
Vlad Yasevich <vyasevich@gmail.com>
Subject: Re: [PATCH net] sctp: linearize early if it's not GSO
Date: Wed, 17 Aug 2016 00:59:17 +0200 [thread overview]
Message-ID: <57B39AC5.7000002@iogearbox.net> (raw)
In-Reply-To: <a4bc263e62ced9f5790932f11e7d829c36566808.1471386679.git.marcelo.leitner@gmail.com>
On 08/17/2016 12:35 AM, Marcelo Ricardo Leitner wrote:
> Because otherwise when crc computation is still needed it's way more
> expensive than on a linear buffer to the point that it affects
> performance.
>
> It's so expensive that netperf test gives a perf output as below:
>
> Overhead Shared Object Symbol
> 69,44% [kernel] [k] gf2_matrix_square
> 2,84% [kernel] [k] crc32_generic_combine.part.0
> 2,78% [kernel] [k] _raw_spin_lock_bh
What kernel is this, seems not net kernel?
$ git grep -n gf2_matrix_square
$ git grep -n crc32_generic_combine
$
Maybe RHEL? Did you consider backporting 6d514b4e7737 et al?
> And performance goes from 2Gbit/s to 0.5Gbit/s on this test. Doing the
> linearization before checksumming is enough to restore it.
>
> Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
next prev parent reply other threads:[~2016-08-16 22:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-16 22:35 [PATCH net] sctp: linearize early if it's not GSO Marcelo Ricardo Leitner
2016-08-16 22:35 ` Marcelo Ricardo Leitner
2016-08-16 22:59 ` Daniel Borkmann [this message]
2016-08-16 22:59 ` Daniel Borkmann
2016-08-17 0:49 ` Marcelo Ricardo Leitner
2016-08-17 0:49 ` Marcelo Ricardo Leitner
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