From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 13 Jul 2001 03:36:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 13 Jul 2001 03:36:05 -0400 Received: from ns.suse.de ([213.95.15.193]:32263 "HELO Cantor.suse.de") by vger.kernel.org with SMTP id ; Fri, 13 Jul 2001 03:35:54 -0400 To: Tim Hockin Cc: linux-kernel@vger.kernel.org Subject: Re: SOMAXCONN - bump up or sysctl? In-Reply-To: <3B4E7EA1.F904DC43@sun.com.suse.lists.linux.kernel> From: Andi Kleen Date: 13 Jul 2001 09:35:49 +0200 In-Reply-To: Tim Hockin's message of "13 Jul 2001 07:09:53 +0200" Message-ID: User-Agent: Gnus/5.0803 (Gnus v5.8.3) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tim Hockin writes: > hey all, > > We have a request to bump up SOMAXCONN. Are there are repurcussions to > doing so? Would it be better to make it a sysctl? Have you checked if the requester is not satisfied with an increase of /proc/sys/net/ipv4/tcp_max_syn_backlog? If they "know" from 2.0 that they want a SOMAXCONN increase then that's very likely the case. In 2.2+ SOMAXCONN only applies to established sockets waiting to get accept()ed; and when you have 128 established sockets that don't get served by accept you have a big problem. SYN-RECV sockets are a completely different thing and they are tuned by the first sysctl and some other heuristics in 2.4. You can also turn on syncookies there to handle syn-recv load spikes. -Andi