From owner-freebsd-alpha Tue Oct 12 20:38:31 1999 Delivered-To: freebsd-alpha@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id 69FA214C32; Tue, 12 Oct 1999 20:38:25 -0700 (PDT) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.1/8.9.1) with ESMTP id XAA21979; Tue, 12 Oct 1999 23:38:23 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.9.3/8.9.1) id XAA51696; Tue, 12 Oct 1999 23:37:53 -0400 (EDT) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Tue, 12 Oct 1999 23:37:53 -0400 (EDT) To: freebsd-alpha@freebsd.org Cc: freebsd-hackers@freebsd.org Subject: alpha scheduling needs some tuning X-Mailer: VM 6.43 under 20.4 "Emerald" XEmacs Lucid Message-ID: <14339.64335.748030.108662@grasshopper.cs.duke.edu> Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Has anybody noticed that scheduling appears to be broken on the alpha? On both i386 & alpha, try: echo "main(){for(;;);}" > foo.c cc foo.c /usr/bin/nice -20 ./a.out & ; ./a.out & & watch the programs run in top. You'll notice that on the i386, the non-niced job will get about 2/3 of the cpu & the niced job will get about one third: PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND 51676 gallatin 94 0 764K 204K RUN 5:37 64.31% 64.31% a.out 51675 gallatin 105 20 764K 204K RUN 2:42 32.71% 32.71% a.out On the alpha, its close to dead even & the nice'd job is actually getting more CPU!: PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND 76397 gallatin 105 20 1168K 960K RUN 4:10 49.61% 49.61% a.out 76398 gallatin 105 0 1168K 960K RUN 4:38 48.00% 48.00% a.out The i386 (a PII) shows this for kern.clockrate: kern.clockrate: { hz = 100, tick = 10000, tickadj = 5, profhz = 1024, stathz = 128 } And the alpha shows this: kern.clockrate: { hz = 1024, tick = 976, tickadj = 5, profhz = 1024, stathz = 1024 } I fully admit that I don't have a good understanding of the scheduling algorithm. I was hoping somebody who does might be able to suggest a fix. Thanks, Drew ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message