From: Wenji Wu <wenji@fnal.gov>
To: Sangtae Ha <sangtae.ha@gmail.com>
Cc: "Ilpo Järvinen" <ilpo.jarvinen@helsinki.fi>,
"John Heffner" <johnwheffner@gmail.com>,
Netdev <netdev@vger.kernel.org>
Subject: Re: A Linux TCP SACK Question
Date: Sun, 06 Apr 2008 15:27:57 -0500 [thread overview]
Message-ID: <fb8e9e4f102e.47f8ebfd@fnal.gov> (raw)
In-Reply-To: <649aecc70804051417l4cf9b30asec8ca8d55e79e051@mail.gmail.com>
> Can you run the attached script and run your testing again?
> I think it might be the problem of your dual cores balance the
> interrupts on your testing NIC.
> As we do a lot of things with SACK, cache misses and etc. might affect
> your performance.
>
> In default setting, I disabled tcp segment offload and did a smp
> affinity setting to CPU 0.
> Please change "INF" to your interface name and let us know the results.
I bound the network interrupts and iperf both the CPU0, and CPU0 will be ilde most of the time. The results are still the same.
At this throughput level, the SACK processing won't take much CPU.
It is not the interrupt/cpu affinity that cause the difference.
I am beleving that it is the ACK reordering that cuase the confusion in the sender, which lead the sender uncecessarily to reduce CWND or REORDERING_THRESHOLD.
wenji
next prev parent reply other threads:[~2008-04-06 20:29 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-04 4:54 A Linux TCP SACK Question Wenji Wu
2008-04-04 16:27 ` John Heffner
2008-04-04 17:49 ` Wenji Wu
2008-04-04 18:07 ` John Heffner
2008-04-04 20:00 ` Ilpo Järvinen
2008-04-04 20:07 ` Wenji Wu
2008-04-04 21:15 ` Wenji Wu
2008-04-04 21:33 ` Ilpo Järvinen
2008-04-04 21:39 ` Ilpo Järvinen
2008-04-04 22:14 ` Wenji Wu
2008-04-05 17:42 ` Ilpo Järvinen
2008-04-05 21:17 ` Sangtae Ha
2008-04-06 20:27 ` Wenji Wu [this message]
2008-04-06 22:43 ` Sangtae Ha
2008-04-07 14:56 ` Wenji Wu
2008-04-08 6:36 ` Ilpo Järvinen
2008-04-08 12:33 ` Wenji Wu
2008-04-08 13:45 ` Ilpo Järvinen
2008-04-08 14:30 ` Wenji Wu
2008-04-08 14:59 ` Ilpo Järvinen
2008-04-08 15:27 ` Wenji Wu
2008-04-08 17:26 ` Ilpo Järvinen
2008-04-14 22:47 ` Wenji Wu
2008-04-15 0:48 ` John Heffner
2008-04-15 8:25 ` Ilpo Järvinen
2008-04-15 18:01 ` Wenji Wu
2008-04-15 22:40 ` John Heffner
2008-04-16 8:27 ` David Miller
2008-04-16 9:21 ` Ilpo Järvinen
2008-04-16 9:35 ` David Miller
2008-04-16 14:50 ` Wenji Wu
2008-04-18 6:52 ` David Miller
2008-08-27 14:38 ` about Linux adaptivly adjusting ssthresh Wenji Wu
2008-08-27 22:48 ` John Heffner
2008-08-28 0:53 ` Wenji Wu
2008-08-28 6:34 ` Ilpo Järvinen
2008-08-28 14:20 ` about Linux adaptivly adjusting dupthresh Wenji Wu
2008-08-28 18:53 ` Ilpo Järvinen
2008-08-28 19:30 ` Wenji Wu
2008-04-16 14:40 ` A Linux TCP SACK Question John Heffner
2008-04-16 15:03 ` Ilpo Järvinen
2008-04-16 14:46 ` Wenji Wu
2008-04-15 15:45 ` Wenji Wu
2008-04-15 16:39 ` Wenji Wu
2008-04-15 17:01 ` John Heffner
2008-04-15 17:08 ` Ilpo Järvinen
2008-04-15 17:23 ` John Heffner
2008-04-15 18:00 ` Matt Mathis
2008-04-15 17:55 ` Wenji Wu
2008-04-08 15:57 ` John Heffner
2008-04-08 14:07 ` John Heffner
2008-04-14 16:10 ` Wenji Wu
2008-04-14 16:48 ` Ilpo Järvinen
2008-04-14 22:07 ` Wenji Wu
2008-04-15 8:23 ` Ilpo Järvinen
2008-04-04 21:40 ` Wenji Wu
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