From owner-freebsd-hackers@FreeBSD.ORG Fri May 1 19:00:45 2009 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A3EBE106566C for ; Fri, 1 May 2009 19:00:45 +0000 (UTC) (envelope-from shuvaev@physik.uni-wuerzburg.de) Received: from mailrelay.rz.uni-wuerzburg.de (mailrelay.rz.uni-wuerzburg.de [132.187.3.28]) by mx1.freebsd.org (Postfix) with ESMTP id 2A90E8FC16 for ; Fri, 1 May 2009 19:00:45 +0000 (UTC) (envelope-from shuvaev@physik.uni-wuerzburg.de) Received: from virusscan.mail (localhost [127.0.0.1]) by mailrelay.mail (Postfix) with ESMTP id 52820199498; Fri, 1 May 2009 20:38:49 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by virusscan.mail (Postfix) with ESMTP id 45B70199496; Fri, 1 May 2009 20:38:49 +0200 (CEST) Received: from mail.physik.uni-wuerzburg.de (wthp192.physik.uni-wuerzburg.de [132.187.40.192]) by mailmaster.uni-wuerzburg.de (Postfix) with ESMTP id 2894D199491; Fri, 1 May 2009 20:38:49 +0200 (CEST) Received: from wep4035 ([132.187.37.35]) by mail.physik.uni-wuerzburg.de (Lotus Domino Release 8.0.2HF443) with ESMTP id 2009050120384746-27689 ; Fri, 1 May 2009 20:38:47 +0200 Received: by wep4035 (sSMTP sendmail emulation); Fri, 1 May 2009 20:38:47 +0200 Date: Fri, 1 May 2009 20:38:47 +0200 From: Alexey Shuvaev To: Yuri Message-ID: <20090501183847.GB47845@wep4035.physik.uni-wuerzburg.de> References: <49FB3F32.2010800@rawbw.com> MIME-Version: 1.0 In-Reply-To: <49FB3F32.2010800@rawbw.com> Organization: Universitaet Wuerzburg User-Agent: Mutt/1.5.18 (2008-05-17) X-MIMETrack: Itemize by SMTP Server on domino1/uni-wuerzburg(Release 8.0.2HF443 | November 25, 2008) at 05/01/2009 08:38:47 PM, Serialize by Router on domino1/uni-wuerzburg(Release 8.0.2HF443 | November 25, 2008) at 05/01/2009 08:38:48 PM, Serialize complete at 05/01/2009 08:38:48 PM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Virus-Scanned: by amavisd-new at uni-wuerzburg.de Cc: freebsd-hackers@freebsd.org Subject: Re: Why top never shows ~100% CPU usage with heavy PCU load? 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: Fri, 01 May 2009 19:00:46 -0000 On Fri, May 01, 2009 at 11:28:02AM -0700, Yuri wrote: > When I run cycle process: main() {for (;;) {}} I never see that it > consumes ~100% CPU. > Instead 'top -C' shows something like this, with numbers fluctuating > around the shown numbers: > > > CPU: 96.2% user, 0.0% nice, 20.0% system, 0.0% interrupt, 0.0% idle > Mem: 653M Active, 995M Inact, 241M Wired, 90M Cache, 112M Buf, 11M Free > Swap: 16G Total, 204M Used, 16G Free, 1% Inuse, 16K In > > PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND > 85422 yuri 1 99 0 2520K 980K RUN 0:21 57.47% cycle > > > [snip] > Strange is 20% system load. The summary line is about all cpus/cores/... Here I have: top: last pid: 48056; load averages: 0.91, 0.38, 0.15 up 12+23:14:39 20:34:58 49 processes: 2 running, 47 sleeping CPU: 50.0% user, 0.0% nice, 0.2% system, 0.0% interrupt, 49.8% idle Mem: 259M Active, 1630M Inact, 537M Wired, 16M Cache, 417M Buf, 1495M Free Swap: 4096M Total, 4096M Free PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND 48032 lexx 1 118 0 2624K 604K CPU1 1 2:31 100.00% bbb ... ~>uname -a FreeBSD wep4035 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Sat Apr 18 20:38:14 CEST 2009 root@wep4035:/usr/obj/usr/src/sys/GENERIC amd64 ~> cat bbb.c int main(void) { for (;;); return; } My $0.02, Alexey.