From owner-freebsd-stable@FreeBSD.ORG Tue Aug 6 15:33:35 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 21D18F06 for ; Tue, 6 Aug 2013 15:33:35 +0000 (UTC) (envelope-from eric@vangyzen.net) Received: from aussmtpmrkps320.us.dell.com (aussmtpmrkps320.us.dell.com [143.166.224.254]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id BF55A2472 for ; Tue, 6 Aug 2013 15:33:34 +0000 (UTC) X-Loopcount0: from 64.238.244.148 X-IronPort-AV: E=Sophos;i="4.89,827,1367989200"; d="scan'208";a="37601175" Message-ID: <520116DE.8030305@vangyzen.net> Date: Tue, 6 Aug 2013 10:31:42 -0500 From: Eric van Gyzen User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:17.0) Gecko/20130702 Thunderbird/17.0.7 MIME-Version: 1.0 To: dave@mischler.com Subject: Re: unexpected idprio 31 behavior on 9.2-BETA2 and 9.2-RC1 References: <1375737316.96778.10.camel@firkin.mischler.com> In-Reply-To: <1375737316.96778.10.camel@firkin.mischler.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: freebsd-stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Aug 2013 15:33:35 -0000 On 08/05/2013 16:15, Dave Mischler wrote: > I have an i5-2500 machine 8GB RAM now running 9.2-RC1 amd64 with the > GENERIC kernel. Today, while still running 9.2-BETA2, I updated my > source tree and started building world with idprio 31 and I looked back > a while later and all the CPU cores and disk were essentially idle, and > hardly any progress had been made on the build. I stopped and restarted > the build without the idle priority setting and it ran fine. Anybody > else seen any of this? Anybody know about any fairly recent changes that > might account for it? > > I did a "rm -rf /usr/src /usr/obj" and loaded a new source tree before > going to RC1. I still see odd behavior at RC1. Sometimes it works just > like it should (i.e. compute bound processes use most/all of the > available CPU time), but a lot of the time both the CPU and disk are > idle (e.g. CPU 97.8% idle, disk 1% busy per systat). I don't think I > ever saw this behavior before while running "make buildworld -j4". Can > anyone else confirm/rebut my findings? Thanks. I can confirm your findings, on 9.1-RELEASE-p5 amd64 GENERIC. I ran $ idprio 31 make buildworld buildkernel > /tmp/build.log 2>&1 < /dev/null & on an otherwise idle amd64 system with 4 CPUs. The first command in the build.log file: rm -rf /usr/obj/home/freebsd/tmp took over three minutes. It should have taken about three /seconds/. "uptime" reported a load average of around 1.00. "top" showed no threads (user or kernel) using CPU. "iostat" showed an average of less than 20 tps on ada0. "rm" was usually in the RUN state. /home/freebsd (src) is UFS+SUJ. /usr/obj is UFS+SU. /tmp/build.log is tmpfs. Both UFS file systems are on ada0: ada0 at ata2 bus 0 scbus2 target 0 lun 0 ada0: ATA-8 SATA 2.x device ata2: at channel 0 on atapci0 atapci0: CPU: Intel(R) Xeon(R) CPU X3430 @ 2.40GHz (2394.04-MHz K8-class CPU) real memory = 8589934592 (8192 MB) FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs FreeBSD/SMP: 1 package(s) x 4 core(s) FreeBSD 9.1-RELEASE-p5 #0 r+94f2ad5: Tue Aug 6 09:40:22 CDT 2013 root@srv5:/usr/obj/home/freebsd/sys/GENERIC amd64 /boot/loader.conf contains: console="comconsole vidconsole" comconsole_speed="115200" comconsole_port="0x2f8" /etc/sysctl.conf is empty. I'll update to releng/9.2 and try again. Eric