From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 21 12:42:05 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E949016A41F for ; Mon, 21 Nov 2005 12:42:05 +0000 (GMT) (envelope-from ray@redshift.com) Received: from outgoing.redshift.com (outgoing.redshift.com [207.177.231.8]) by mx1.FreeBSD.org (Postfix) with ESMTP id C18FA43D45 for ; Mon, 21 Nov 2005 12:42:05 +0000 (GMT) (envelope-from ray@redshift.com) Received: from workstation (216-228-19-21.dsl.redshift.com [216.228.19.21]) by outgoing.redshift.com (Postfix) with SMTP id 8E20A97A3A; Mon, 21 Nov 2005 04:42:04 -0800 (PST) Message-Id: <3.0.1.32.20051121044201.00aa1490@pop.redshift.com> X-Mailer: na X-Sender: redshift.com Date: Mon, 21 Nov 2005 04:42:01 -0800 To: "Konstantin Prokazoff" , From: ray@redshift.com In-Reply-To: <0a7a01c5ee75$b300b700$0c02010a@svr012> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Subject: Re: poll()/select() X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Nov 2005 12:42:06 -0000 At 10:29 AM 11/21/2005 +0200, Konstantin Prokazoff wrote: | Welcome everybody, | | have a strange issue under 5.x/6.x (checked). | When using a poll()/select() mechanism, which in kernel based on | selrecord/selwakeup (pollscan, kern_select) functions, we have deadlock on | sellock mutex on heavy load (recursive lock on non-recursive mutex). Have | anyone seen this? Deadlock can be reached only if kernel w'be compiled with | debugger, because in different case system locks, your can't login, etc. | Maybe one path to resolve - change behavour of sched_lock & sellock mutexes | block/unblock order. | Thnx in advance & for comments. | | Best regards, | Konstantin Prokazoff | Center Of Excellence, S_V_R Ltd., Kyiv HQs, Ukraine | Official business-partner & DevConnect member of Avaya Inc. | Regional development & support center of Digium Inc. | Tel. +38 044 244 1181, ext. 1038 | Fax. +38 044 234 0455 The only thing I can add is that a sys admin friend of mine did try using the poll/select to increase performance and had to finally abandon it due to instability problems under load. I've never tried it first hand myself. Not sure if that helps you. Ray