From owner-freebsd-multimedia Thu Jun 4 11:04:22 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA25875 for freebsd-multimedia-outgoing; Thu, 4 Jun 1998 11:04:22 -0700 (PDT) (envelope-from owner-freebsd-multimedia@FreeBSD.ORG) Received: from north.lcs.mit.edu (north.lcs.mit.edu [18.26.0.4]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id LAA25852 for ; Thu, 4 Jun 1998 11:04:18 -0700 (PDT) (envelope-from mjh@north.lcs.mit.edu) Received: from north.lcs.mit.edu by north.lcs.mit.edu (SMI-8.6/SMI-SVR4) id OAA03712; Thu, 4 Jun 1998 14:03:59 -0400 From: Mark Handley X-Organisation: Information Sciences Institute, USC X-Phone: +1 617 253 6011 To: Jim Lowe cc: multimedia@FreeBSD.ORG Subject: Re: Tick, tock, I need a fast clock... In-reply-to: Your message of "Thu, 04 Jun 1998 11:28:49 CDT." <199806041628.LAA02532@miller.cs.uwm.edu> Date: Thu, 04 Jun 1998 14:03:59 -0400 Message-ID: <3710.896983439@north.lcs.mit.edu> Sender: owner-freebsd-multimedia@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org >Are there any timers available to applications in FreeBSD faster than >10ms? If not, is there a simple way to increase the interval timers >minimal time to something like .1ms without adversely effecting system >performance? I has the same requirement earlier this week. You can change the value of HZ in /usr/src/sys/conf/param.c from the default value of 100 to something larger and rebuild. My system is currently running with this set to 1000, which allows interval timers using select of around 2ms (why isn't it 1ms??). The system seems to run fine, but the values measured for per-process CPU utilization by top (and presumably other utilities) are low by an order of magnitude. Presumably this is a bug in some of the kernel stats code. It does seem somewhat rediculous that HZ is still set to 100 by default in these days of 400MHz processors. Cheers, Mark To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message