From: Andi Kleen <andi@firstfloor.org>
To: lsorense@csclub.uwaterloo.ca (Lennart Sorensen)
Cc: Jack Harvard <jack.harvard@googlemail.com>, linux-kernel@vger.kernel.org
Subject: Re: gettimeofday() resolution in Linux?
Date: Thu, 10 Apr 2008 17:35:25 +0200 [thread overview]
Message-ID: <87fxttn2o2.fsf@basil.nowhere.org> (raw)
In-Reply-To: <20080410150424.GD2160@csclub.uwaterloo.ca> (Lennart Sorensen's message of "Thu, 10 Apr 2008 11:04:24 -0400")
lsorense@csclub.uwaterloo.ca (Lennart Sorensen) writes:
>
> On many systems gettimeofday uses the TSC, but on many multicore systems
> the TSC on each core may be out of sync, in which case the cpu you are
> running on may give a different gettimeofday result than another cpu,
> which is probably a bad thing for some processes.
In this case Linux falls back to other timers which are slower and
less accurate.
jiffies based gettimeofday is theoretically possible, but near
never used.
-Andi
next prev parent reply other threads:[~2008-04-10 15:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-10 14:40 gettimeofday() resolution in Linux? Jack Harvard
2008-04-10 15:04 ` Lennart Sorensen
2008-04-10 15:35 ` Andi Kleen [this message]
2008-04-10 15:59 ` Jack Harvard
2008-04-10 17:41 ` Bart Van Assche
[not found] ` <a72f6a3c0804101057i10c572bak1dd09f0c7fd75d30@mail.gmail.com>
2008-04-10 18:02 ` Bart Van Assche
2008-04-10 15:49 ` Chris Friesen
2008-04-10 16:07 ` Bart Van Assche
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