From owner-freebsd-hackers@FreeBSD.ORG Wed Nov 2 09:20:44 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 00A5716A41F for ; Wed, 2 Nov 2005 09:20:43 +0000 (GMT) (envelope-from viktor.vasilev@stud.tu-darmstadt.de) Received: from lnx117.hrz.tu-darmstadt.de (lnx117.hrz.tu-darmstadt.de [130.83.174.26]) by mx1.FreeBSD.org (Postfix) with ESMTP id 428A743D45 for ; Wed, 2 Nov 2005 09:20:38 +0000 (GMT) (envelope-from viktor.vasilev@stud.tu-darmstadt.de) Received: from ilium.0xdeadc0de.net (ABC216.ram1st.wh.tu-darmstadt.de [130.83.20.203]) (authenticated bits=0) by lnx117.hrz.tu-darmstadt.de (8.12.10/8.12.10) with ESMTP id jA29KG3i007383; Wed, 2 Nov 2005 10:20:16 +0100 Received: by ilium.0xdeadc0de.net (nbSMTP-1.00) for uid 1001 viktor.vasilev@stud.tu-darmstadt.de; Wed, 2 Nov 2005 10:20:22 +0100 (CET) Date: Wed, 2 Nov 2005 10:20:22 +0100 From: Viktor Vasilev To: Mike Silbersack Message-ID: <20051102092022.GA624@ilium.0xdeadc0de.net> References: <20051101224223.GA737@ilium.0xdeadc0de.net> <20051102012953.C815@odysseus.silby.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051102012953.C815@odysseus.silby.com> X-Operating-System: FreeBSD 5.4-RELEASE i386 User-Agent: mutt-ng devel (FreeBSD) X-TUD-HRZ-MailScanner: Found to be clean X-TUD-HRZ-MailScanner-SpamCheck: X-MailScanner-From: viktor.vasilev@stud.tu-darmstadt.de Cc: freebsd-hackers@freebsd.org Subject: Re: select(2) timeout precision 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: Wed, 02 Nov 2005 09:20:44 -0000 On Wed, Nov 02, 2005 at 01:31:39AM -0600, Mike Silbersack wrote: > > On Tue, 1 Nov 2005, Viktor Vasilev wrote: > > >With FreeBSD 5.4-RELEASE I almost constantly get ~20000 microseconds > >delta. That is with 100HZ kernel on PIII 500MHz or Sempron 64 2800+ > > Put kern.hz=1000 in /boot/loader.conf to kick it up to 1000Hz, that > should improve the accuracy a lot. Indeed! That did the trick. > The optimizations in the url someone else posted should probably be > integrated into FreeBSD, but moving to a higher Hz setting is a > necessity in either case. I've read in the lists, that in -CURRENT 1000HZ and PREEMPTION are in the GENERIC kernel. It'll be interesting to see how it performs there. With 6.0 around the corner, I'll give it a try soon. Thank you and Mihail Balikov for the pointers. Cheers, Viktor -- I think and think for months and years. Ninety nine times, the conclusion is false. The hundredth time I am right. -- Albert Einstein