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 19:28:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 13 Nov 2001 19:28:05 -0500 Received: from ikura.fe.dis.titech.ac.jp ([131.112.171.65]:24798 "HELO ikura.fe.dis.titech.ac.jp") by vger.kernel.org with SMTP id ; Tue, 13 Nov 2001 19:27:47 -0500 Date: Wed, 14 Nov 2001 09:27:39 +0900 Message-ID: From: GOTO Masanori To: jakob@unthought.net, linux-kernel@vger.kernel.org Subject: Re: High UNIX socket latency In-Reply-To: In your message of "Tue, 13 Nov 2001 12:51:26 +0100" <20011113125126.E30421@unthought.net> In-Reply-To: <20011113125126.E30421@unthought.net> User-Agent: EMIKO/1.13.9 (Euglena tripteris) FLIM/1.13.2 (Kasanui) APEL/10.2 MULE XEmacs/21.1 (patch 10) (Capitol Reef) (i386-debian-linux) MIME-Version: 1.0 (generated by EMIKO 1.13.9 - "Euglena tripteris") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org At Tue, 13 Nov 2001 12:51:26 +0100, Jakob Ostergaard wrote: > 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. I think more details are needed... kernel version, packet size, select timeout, your program/environment, the result of average responce time and each responce time, throughput, etc. -- gotom