Date: Sun, 3 Jan 1999 19:21:05 -0800 (PST) From: Julian Elischer <julian@whistle.com> To: Mohit Aron <aron@cs.rice.edu> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: fine-grained timers Message-ID: <Pine.BSF.3.95.990103191435.29200E-100000@current1.whistle.com> In-Reply-To: <199901031742.LAA21838@cs.rice.edu>
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You should use the calls acquire_timer0() and release_timer0() which are found in /sys/i386/isa/clock.c They allow you to change the underlying hardware clock frequency to a multiple of "hz" (usually 100 Hz) nad still have the system act as if the hardware were running at 'hz'. On each real h/w clock interrupt your nominated function is called. the pcaudio driver (i386/isa/pcaudio.c) uses this tu run teh hardware clock at 16000Hz which is faster than you require. Unfortunatly only one higher speed can be used at a time (of course!). On Sun, 3 Jan 1999, Mohit Aron wrote: > Hi, > I'm using FreeBSD-2.2.6. I want to make FreeBSD generate timer > interrupts with a granularity as fine as 100usecs. Since the hardclock() > operates at a 10ms granularity, its not of much use. I also want to disable > dynamically the fine-grained interrupts, so I don't want to simply modify the > granularity at which hardclock gets called. Can someone > suggest the functions or places in the kernel which I should modify to > register my own interrupt handler. Thanks, > > > > - Mohit > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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