From mboxrd@z Thu Jan 1 00:00:00 1970 From: lm@bitmover.com (Larry McVoy) Subject: Re: tcp bw in 2.6 Date: Tue, 2 Oct 2007 08:41:37 -0700 Message-ID: <20071002154137.GD17418@bitmover.com> References: <20071002005917.GB5480@bitmover.com> <20071002150935.GC17418@bitmover.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: lm@bitmover.com, Herbert Xu , torvalds@linux-foundation.org, davem@davemloft.net, wscott@bitmover.com, netdev@vger.kernel.org Return-path: Received: from ipcop.bitmover.com ([192.132.92.15]:43325 "EHLO mail.bitmover.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752754AbXJBPli (ORCPT ); Tue, 2 Oct 2007 11:41:38 -0400 Content-Disposition: inline In-Reply-To: <20071002150935.GC17418@bitmover.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Interesting data point. My test case is like this: server bind listen while (newsock = accept...) transfer() client connect transfer If the server side is the source of the data, i.e, it's transfer is a write loop, then I get the bad behaviour. If I switch them so the data flows in the other direction, then it works, I go from about 14K pkt/sec to 43K pkt/sec. Can anyone else reproduce this? I can extract the test case from lmbench so it is standalone but I suspect that any test case will do it. I'll try with the one that John sent. Yup, s/read/write/ and s/write/read/ in his two files at the appropriate places and I get exactly the same behaviour. So is this a bug or intentional? -- --- Larry McVoy lm at bitmover.com http://www.bitkeeper.com