From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wenji Wu <wenji@fnal.gov>
Subject: RE: A Linux TCP SACK Question
Date: Mon, 14 Apr 2008 11:10:06 -0500
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Cc: 'Sangtae Ha' <sangtae.ha@gmail.com>,
	'John Heffner' <johnwheffner@gmail.com>,
	'Netdev' <netdev@vger.kernel.org>
To: =?iso-8859-1?Q?'Ilpo_J=E4rvinen'?= <ilpo.jarvinen@helsinki.fi>
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 id <0JZB00501OUHEY@mailgw1.fnal.gov> (original mail from wenji@fnal.gov)
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Hi, Ilop,

The latest results have been posted to:

https://plone3.fnal.gov/P0/WAN/Members/wenji/tcp_dump_files_sack/

The kernel under test is: Linux-2.6.25-rc9. I have checked with its
changelog, which shows that your latest fix is included.

In the tests, I vary the tcp_frto (0, 1, and 2) with SACK On/Off.

The experiment works as:

      Sender --- Router --- Receiver

Iperf is sending from the sender to the receiver. In between there is an
emulated router which runs netem. The emulated router has two interfaces,
both with netem configured.  One interface emulates the forward path and the
other for the reverse path. Both netem interfaces are configured with 1.5ms
delay and 0.15ms variance. No packet drops in tests and packet capturing.

All of these systems are multi-core platforms, with 2G+ CPU. I run
TOP to verify, CPUs are idle most of time.

wenji