Date: Tue, 01 May 2001 02:08:07 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Mike Smith <msmith@FreeBSD.ORG> Cc: Terry Lambert <tlambert@primenet.com>, Rolf Neugebauer <neugebar@dcs.gla.ac.uk>, freebsd-alpha@FreeBSD.ORG Subject: Re: determine cycle counter frequency in user space Message-ID: <3AEE7CF7.69D87D5F@mindspring.com> References: <200104302157.f3ULvvv02259@mass.dis.org>
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Mike Smith wrote: > Use time_second for coarse timing requirements. [ ... ] > The cycle counter can't be relied on. Get this through your > thick head. The clock frequency on many Alpha systems is > unstable, and on most PCs, it can change out from under you > with no warning. [ ... ] > Hardware sucks; what can I say? You can't do this usefully > in userspace; stop trying and go buy some real timing hardware > if you actually care. Sorry; I didn't get this message in time. Unfortunately, my code is now working with ~90uS accuracy, +/- 90uS. I'll try to be more dilligent in keeping up with my email from now on... ;-). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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