From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: <xen-devel@lists.xensource.com>
Cc: <linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>,
<christoffer.dall@linaro.org>,
Ian Campbell <Ian.Campbell@citrix.com>,
"Wei Liu" <wei.liu2@citrix.com>,
David Vrabel <david.vrabel@citrix.com>, <edumazet@google.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: "tcp: refine TSO autosizing" causes performance regression on Xen
Date: Thu, 9 Apr 2015 16:46:30 +0100 [thread overview]
Message-ID: <alpine.DEB.2.02.1504091344260.7690@kaball.uk.xensource.com> (raw)
Hi all,
I found a performance regression when running netperf -t TCP_MAERTS from
an external host to a Xen VM on ARM64: v3.19 and v4.0-rc4 running in the
virtual machine are 30% slower than v3.18.
Through bisection I found that the perf regression is caused by the
prensence of the following commit in the guest kernel:
commit 605ad7f184b60cfaacbc038aa6c55ee68dee3c89
Author: Eric Dumazet <edumazet@google.com>
Date: Sun Dec 7 12:22:18 2014 -0800
tcp: refine TSO autosizing
A simple revert would fix the issue.
Does anybody have any ideas on what could be the cause of the problem?
Suggestions on what to do to fix it?
Cheers,
Stefano
next reply other threads:[~2015-04-09 15:49 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-09 15:46 Stefano Stabellini [this message]
2015-04-09 16:16 ` Eric Dumazet
2015-04-09 16:36 ` Stefano Stabellini
2015-04-09 17:07 ` Eric Dumazet
2015-04-13 10:56 ` [Xen-devel] " George Dunlap
2015-04-13 13:38 ` Jonathan Davies
2015-04-13 13:49 ` Eric Dumazet
2015-04-15 13:43 ` George Dunlap
2015-04-15 16:38 ` Eric Dumazet
2015-04-15 17:23 ` George Dunlap
2015-04-15 17:29 ` Eric Dumazet
2015-04-15 17:41 ` George Dunlap
2015-04-15 17:52 ` Eric Dumazet
2015-04-15 17:55 ` Rick Jones
2015-04-15 18:08 ` Eric Dumazet
2015-04-15 18:19 ` Rick Jones
2015-04-15 18:32 ` Eric Dumazet
2015-04-15 20:08 ` Rick Jones
2015-04-15 18:04 ` George Dunlap
2015-04-15 18:19 ` Eric Dumazet
2015-04-16 8:56 ` George Dunlap
2015-04-16 9:20 ` Daniel Borkmann
2015-04-16 10:01 ` George Dunlap
2015-04-16 12:42 ` Eric Dumazet
2015-04-20 11:03 ` George Dunlap
2015-06-02 9:52 ` Wei Liu
2015-06-02 16:16 ` Eric Dumazet
2015-04-16 9:22 ` David Laight
2015-04-16 10:57 ` George Dunlap
2015-04-15 17:41 ` Eric Dumazet
2015-04-15 17:58 ` Stefano Stabellini
2015-04-15 18:17 ` Eric Dumazet
2015-04-16 4:20 ` Herbert Xu
2015-04-16 4:30 ` Eric Dumazet
2015-04-16 11:39 ` George Dunlap
2015-04-16 12:16 ` Eric Dumazet
2015-04-16 13:00 ` Tim Deegan
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