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From: Eyal Perry <eyalpe@dev•mellanox.co.il>
To: eric.dumazet@gmail•com
Cc: netdev@vger•kernel.org, Amir Vadai <amirv@mellanox•com>,
	yevgenyp@mellanox•com, saeedm@mellanox•com, idos@mellanox•com,
	amira@mellanox•com, eyalpe@mellanox•com
Subject: BW regression after "tcp: refine TSO autosizing"
Date: Tue, 13 Jan 2015 18:48:50 +0200	[thread overview]
Message-ID: <54B54C72.8060705@dev.mellanox.co.il> (raw)

Hello Eric,
Lately we've observed performance degradation in BW of about 30-40% (depends on
the setup we use).
I've bisected the issue down to the this commit: 605ad7f1 ("tcp: refine TSO
autosizing")

For instance, I was running the following test:
1. Bounding net device' irqs to core 0 for both client and server side
2. Running netperf with 64K massage size (used the following command)
$ netperf -H remote -T 1,1 -l 100 -t TCP_STREAM -- -k THROUGHPUT -M 65536 -m 65536

I ran the test on upstream net-next including your patch and than reverted it
and these are the results I got was improvement from 14.6Gbps to 22.1Gbps.

an additional difference I've noticed when inspecting the ethtool statics,
number of xmit_more packets increased from 4 to 160 with the reverted kernel.

We are investigating this issue, do you have a hint?

Best regards,
Eyal.

             reply	other threads:[~2015-01-13 16:54 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-13 16:48 Eyal Perry [this message]
2015-01-13 18:57 ` BW regression after "tcp: refine TSO autosizing" Eric Dumazet
2015-01-13 20:21   ` Or Gerlitz
2015-01-13 21:41     ` Eyal Perry
2015-01-13 22:00       ` Eric Dumazet
2015-01-18 16:22         ` Eyal Perry
2015-01-18 17:48           ` Eric Dumazet
2015-01-18 21:40             ` Eyal Perry
2015-01-20  2:16               ` Eric Dumazet
2015-01-20  2:37                 ` Dave Taht
2015-01-20  3:14                   ` Eric Dumazet
2015-01-20 19:14                     ` Rick Jones
2015-01-20 19:26                       ` Eric Dumazet
2015-01-20 19:44                         ` Rick Jones
2015-01-21 12:26                       ` David Laight
2015-01-21 17:01                         ` Eric Dumazet

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