From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 13 Nov 2001 06:51:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 13 Nov 2001 06:51:44 -0500 Received: from unthought.net ([212.97.129.24]:62906 "HELO mail.unthought.net") by vger.kernel.org with SMTP id ; Tue, 13 Nov 2001 06:51:28 -0500 Date: Tue, 13 Nov 2001 12:51:26 +0100 From: =?iso-8859-1?Q?Jakob_=D8stergaard?= To: linux-kernel@vger.kernel.org Subject: High UNIX socket latency Message-ID: <20011113125126.E30421@unthought.net> Mail-Followup-To: =?iso-8859-1?Q?Jakob_=D8stergaard?= , linux-kernel@vger.kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello all, One program that creates a pipe between two processes and measures the ping/pong latency of messages between the two processes gives me something like; 1000 iterations - ping/pong time max = 3495 us min = 6 us avg = 47.212 us In another application where I use a UNIX STREAM socket, I get a typical latency of one send() of around 1 ms. I cannot set TCP_NODELAY on a UNIX socket, and I can't really see why I get the high latency. Is there some undocumented option like TCP_NODELAY for UNIX STREAM connections, or are there other tricks I can play to get the latency down ? One process does a send(), the other one does a select() and a recv() - and the time from the send() to the recv() is around 1 ms which I think seems far too high. Hints, suggestions ? Thank you -- ................................................................ : jakob@unthought.net : And I see the elder races, : :.........................: putrid forms of man : : Jakob Østergaard : See him rise and claim the earth, : : OZ9ABN : his downfall is at hand. : :.........................:............{Konkhra}...............: