From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 9 Aug 2001 15:00:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 9 Aug 2001 15:00:33 -0400 Received: from [206.166.249.112] ([206.166.249.112]:44038 "EHLO srv-exchange2.adtran.com") by vger.kernel.org with ESMTP id ; Thu, 9 Aug 2001 15:00:22 -0400 Message-ID: <3B72DD74.199F31B7@adtran.com> Date: Thu, 09 Aug 2001 13:59:00 -0500 From: Ron Flory Organization: Adtran X-Mailer: Mozilla 4.77 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 CC: linux-kernel@vger.kernel.org Subject: Re: Kernel 2.4.6 & 2.4.7 networking performance: seeing serious delays inTCP layer depending upon packet length In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit To: unlisted-recipients:; (no To-header on input)@localhost.localdomain Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Shirley Ma wrote: > > Hi, Ron, > > I am interested the problem you posted. I tried to reproduce > this problem on my machine and failed. Would you please point your > programs to me, so I can reproduce this problem and do more > investigation? If not, please let me know whether it is reproducible, > and please collect both client/server ethereal log. OK, will follow-on in a private email (to minimize lkml traffic) I can easily reproduce the problem by performing a socket 'write' as two separate operations: write(sock, buf1..) write(sock, buf2..) If on the other hand I combine the buffers then issue a single 'write': write(sock, both_bufs...) the problem magically disappears (because the inter-block handshaking requirements change, which is where I think the problem actually lies). Since the problem is also present using the loopback device, both client/server sides would be present in a Ethereal long of LO. I would imagine anybody running a large Linux ftp/http server would be interested in this... ron