Date: Tue, 01 Jan 2002 17:45:35 -0800 From: Mike Smith <msmith@freebsd.org> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Bruce Evans <bde@zeta.org.au>, arch@FreeBSD.ORG Subject: Re: When to use atomic_ functions? (was: 64 bit counters) Message-ID: <200201020145.g021jZr03903@mass.dis.org> In-Reply-To: Your message of "Tue, 01 Jan 2002 15:49:20 PST." <200201012349.g01NnKA40071@apollo.backplane.com>
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>
> :On Tue, 1 Jan 2002, Mike Smith wrote:
> :>
> :> It's imperative to use atomic operations for counters on SMP systems.
> :
> :Not true. Atomic operations for counters are not needed on SMP systems
> :in at least the following cases:
> :- if there is a lock that prevents other processes from accessing the
> : counter
> :- if the counters are per-CPU. See previous mail by someone named msmith.
8) Sorry, I should have been more explicit, rather than assuming that
the audience would read the implicit exclusion of alternatives into the
above.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
V I C T O R Y N O T V E N G E A N C E
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