From: Eric Dumazet <eric.dumazet@gmail.com>
To: Ben Greear <greearb@candelatech.com>, netdev <netdev@vger.kernel.org>
Subject: Re: Performance regression between 4.13 and 4.14
Date: Tue, 8 May 2018 10:10:27 -0700 [thread overview]
Message-ID: <b411b57e-9d2f-3ca0-f9b7-19dd2238675c@gmail.com> (raw)
In-Reply-To: <9115910b-dd8b-e7f3-be53-f739b8382032@candelatech.com>
On 05/08/2018 09:44 AM, Ben Greear wrote:
> Hello,
>
> I am trying to track down a performance regression that appears to be between 4.13
> and 4.14.
>
> I first saw the problem with a hacked version of pktgen on some ixgbe NICs. 4.13 can do
> right at 10G bi-directional on two ports, and 4.14 and later can do only about 6Gbps.
>
> I also tried with user-space UDP traffic on a stock kernel, and I can get about 3.2Gbps combined tx+rx
> on 4.14 and about 4.4Gbps on 4.13.
>
> Attempting to bisect seems to be triggering a weirdness in git, and also lots of commits
> crash or do not bring up networking, which makes the bisect difficult.
>
> Looking at perf top, it would appear that some lock is probably to blame.
perf record -a -g -e cycles:pp sleep 5
perf report
Then you'll be able to tell us which lock (or call graph) is killing your perf.
next prev parent reply other threads:[~2018-05-08 17:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-08 16:44 Performance regression between 4.13 and 4.14 Ben Greear
2018-05-08 17:10 ` Eric Dumazet [this message]
2018-05-09 18:43 ` Ben Greear
2018-05-09 18:48 ` Eric Dumazet
2018-05-09 19:02 ` Ben Greear
2018-05-09 20:55 ` Ben Greear
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