From owner-freebsd-arch  Wed Jan  2 19:52:36 2002
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Date: Wed, 02 Jan 2002 19:52:32 -0800
From: Terry Lambert <tlambert2@mindspring.com>
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To: Bernd Walter <ticso@cicely9.cicely.de>
Cc: Matthew Dillon <dillon@apollo.backplane.com>,
	John Baldwin <jhb@FreeBSD.ORG>, arch@FreeBSD.ORG,
	Bernd Walter <ticso@cicely8.cicely.de>,
	Mike Smith <msmith@FreeBSD.ORG>, Bruce Evans <bde@zeta.org.au>,
	Michal Mertl <mime@traveller.cz>,
	Peter Jeremy <peter.jeremy@alcatel.com.au>
Subject: Re: When to use atomic_ functions? (was: 64 bit counters)
References: <XFMail.020102152920.jhb@FreeBSD.org> <200201030002.g0302Eo60575@apollo.backplane.com> <20020103003214.GC53199@cicely9.cicely.de>
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Bernd Walter wrote:
> You need to hold the mutex while writing and reading.
> If you hold the mutex only while writing another CPU might still use
> old cached values.


Unless there are two sounts that MUST remain synchornized for
correct operation, you don't *care* if someone gets the stale
value.

Ask yourself: what's the worst case failure scenario that would
result?


-- Terry

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