Date: Thu, 24 Jun 1999 12:39:22 -0700 (PDT) From: schuerge@cs.uni-sb.de To: freebsd-gnats-submit@freebsd.org Subject: kern/12381: Bad scheduling in FreeBSD Message-ID: <19990624193922.9C9F2153CB@hub.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 12381 >Category: kern >Synopsis: Bad scheduling in FreeBSD >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Jun 24 12:40:00 PDT 1999 >Closed-Date: >Last-Modified: >Originator: Thomas Schürger >Release: FreeBSD 4.0-CURRENT >Organization: Universität Saarbrücken, Germany >Environment: FreeBSD starfire.heim-d.uni-sb.de 4.0-CURRENT FreeBSD 4.0-CURRENT #0: Tue Jun 15 13:36:03 CEST 1999 schuerge@starfire.heim-d.uni-sb.de:/usr/src/sys/compile/STARFIRE i386 >Description: FreeBSD does not seem to schedule processes properly. When starting two CPU-intensive processes, one running with nice-level 0, the other with nice-level 20, the first process will get 66%, the second one 33% of the available CPU time, so a 2:1 time-slicing is done. This can easily be verified by starting two Perl scripts containing just an endless loop and renicing one of them to +20. "top" will display what's written above. This cannot be a bug of "top", as the process' used CPU times increase in the same way. Other Unix variants do a much better time-slicing. I've tested the same on a fast Solaris machine and Solaris does a 10:1 slicing, that is 9% for the background and 91% for the foreground process, which is more desirable. It seems that renicing a process does not have a lot of effect in FreeBSD. >How-To-Repeat: The problem can be verified by starting two CPU-intensive processes, renicing one to +20 and watching the "top" output. >Fix: >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19990624193922.9C9F2153CB>