From owner-freebsd-alpha  Tue May  1  2: 7:57 2001
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Date: Tue, 01 May 2001 02:08:07 -0700
From: Terry Lambert <tlambert2@mindspring.com>
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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
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

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