From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 20 Jan 2001 19:32:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 20 Jan 2001 19:32:39 -0500 Received: from mailout3-0.nyroc.rr.com ([24.92.226.118]:8959 "EHLO mailout3-0.nyroc.rr.com") by vger.kernel.org with ESMTP id ; Sat, 20 Jan 2001 19:32:24 -0500 Message-ID: <022f01c08342$088f67b0$0701a8c0@morph> From: "Dan Maas" To: "Edgar Toernig" , "Michael Lindner" Cc: "Chris Wedgwood" , In-Reply-To: <015e01c082ac$4bf9c5e0$0701a8c0@morph> <3A69361F.EBBE76AA@att.net> <20010120200727.A1069@metastasis.f00f.org> <3A694254.B52AE20B@att.net> <3A6A09F2.8E5150E@gmx.de> Subject: Re: PROBLEM: select() on TCP socket sleeps for 1 tick even if data available Date: Sat, 20 Jan 2001 19:35:12 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > It's not the select that waits. It's a delay in the tcp send > path waiting for more data. Try disabling it: > > int f=1; > setsockopt(s, SOL_TCP, TCP_NODELAY, &f, sizeof(f)); Bingo! With this fix, 2.2.18 performance becomes almost identical to 2.4.0 performance. I assume 2.4.0 disables Nagle by default on local connections... Dan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/