From owner-freebsd-questions@FreeBSD.ORG Tue Oct 17 02:52:35 2006 Return-Path: X-Original-To: freebsd-questions@FreeBSD.org Delivered-To: freebsd-questions@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DE04F16A403; Tue, 17 Oct 2006 02:52:35 +0000 (UTC) (envelope-from on@cs.ait.ac.th) Received: from mail.cs.ait.ac.th (mail.cs.ait.ac.th [192.41.170.16]) by mx1.FreeBSD.org (Postfix) with ESMTP id 72E2D43D96; Tue, 17 Oct 2006 02:52:15 +0000 (GMT) (envelope-from on@cs.ait.ac.th) Received: from banyan.cs.ait.ac.th (banyan.cs.ait.ac.th [192.41.170.5]) by mail.cs.ait.ac.th (8.13.1/8.12.11) with ESMTP id k9H2q3nm083508 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 17 Oct 2006 09:52:03 +0700 (ICT) Received: (from on@localhost) by banyan.cs.ait.ac.th (8.13.3/8.12.11) id k9H2qHaD012527; Tue, 17 Oct 2006 09:52:17 +0700 (ICT) Date: Tue, 17 Oct 2006 09:52:17 +0700 (ICT) Message-Id: <200610170252.k9H2qHaD012527@banyan.cs.ait.ac.th> From: Olivier Nicole To: grog@FreeBSD.org In-reply-to: <20061017024102.GO96445@wantadilla.lemis.com> (grog@FreeBSD.org) References: <200610170235.k9H2ZElx012419@banyan.cs.ait.ac.th> <20061017024102.GO96445@wantadilla.lemis.com> X-Virus-Scanned: on CSIM by amavisd-milter (http://www.amavis.org/) Cc: freebsd-questions@FreeBSD.org Subject: Re: User vs Kernel mode X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Oct 2006 02:52:36 -0000 > Processes always start in kernel mode, because they're started by the > kernel. They typically spend most of their time in kernel mode (for > example, whenever they're idle or waiting for I/O). An active process > may switch back and forward between kernel mode and user mode > thousands of times a second. Thanks for the clarification. > Maybe you should describe your problem. The application has been working fine for almost 3 years, along with Apache, going through RELENG upgrade without problem. Now I start noticing that Apache hangs (sig 11), either manually built or port built, make buildworld hanged once with sig 11, my application hangs with sig 11. 2 options: - I added memory in the machine and the meory is causing problems. - I changed my application a little bit and it started eating other processes. Yesterday make buildworld consistenly hanged on building groff, today after cleaning the memory (using plain rubber on DIMM contacts) it is going fine (although Apache did hang since the cleaning). So I'd like to be sure that my application cannot eat other processes, so i could eliminate one cause. Bests, Olivier