Date: 02 Jul 1998 15:11:13 +0200 From: smoergrd@oslo.geco-prakla.slb.com (Dag-Erling Coidan Smørgrav) To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: sos@FreeBSD.ORG, nick.hibma@jrc.it, hackers@FreeBSD.ORG Subject: Re: timeout granularity (was: Re: Console driver...) Message-ID: <rx4emw42ya6.fsf@oslo.geco-prakla.slb.com> In-Reply-To: Luigi Rizzo's message of Thu, 2 Jul 1998 13:26:59 %2B0200 (MET DST) References: <199807021127.NAA12406@labinfo.iet.unipi.it>
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Luigi Rizzo <luigi@labinfo.iet.unipi.it> writes: > [about default timer granularity being too coarse for sampling > the vertical retrace interval] > > the code might check if HZ is set to a suitable value (how large, > e.g. 1000 or 2000, i have no idea) and use timeout instead of > polling if the test is successful. Sooner or later hopefully we > will move to large values of HZ anyways. > > (or, how about adding a utimeout() call to the kernel :) It's not that simple. You have to know how long to wait, which is practically impossible to do without hooking the timer interrupt and reprogramming it to keep pace with the retrace, and even that is difficult to achieve without a little busy-waiting here and there. DES -- Dag-Erling Smørgrav - smoergrd@oslo.geco-prakla.slb.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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