From: Andi Kleen <ak@suse.de>
To: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
Christopher Friesen <cfriesen@nortel.com>,
Russell King <rmk+lkml@arm.linux.org.uk>,
linux-kernel@vger.kernel.org
Subject: Re: sched_clock() uses are broken
Date: Wed, 3 May 2006 09:40:19 +0200 [thread overview]
Message-ID: <200605030940.20409.ak@suse.de> (raw)
In-Reply-To: <1146640155.7526.27.camel@homer>
On Wednesday 03 May 2006 09:09, Mike Galbraith wrote:
> Given that most people are going to end up using the pm_timer anyway, I
> don't see the point of even having a sched_clock(). If it's jiffy
> resolution, it's useless. If it's wildly inaccurate (as it is in the
> SMP case, monotonicity issues aside) it's more than useless.
For sched_clock TSC is always used and it's fine - sched_clock
doesn't require the guarantees that make TSC often useless otherwise
e.g. the scheduler is designed to only use it on one CPU
and can also tolerate variations scaling with frequency.
-Andi
next prev parent reply other threads:[~2006-05-03 7:40 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-02 13:29 sched_clock() uses are broken Russell King
2006-05-02 14:21 ` Nick Piggin
2006-05-02 16:43 ` Andi Kleen
2006-05-02 16:50 ` Russell King
2006-05-02 17:01 ` Andi Kleen
2006-05-02 17:18 ` Nicolas Pitre
2006-05-02 18:55 ` Russell King
2006-05-02 19:05 ` Nicolas Pitre
2006-05-02 19:08 ` Russell King
2006-05-02 19:23 ` Nicolas Pitre
2006-05-02 21:35 ` Russell King
2006-05-02 17:15 ` Nicolas Pitre
2006-05-04 3:50 ` George Anzinger
2006-05-04 14:18 ` Nicolas Pitre
2006-05-02 16:54 ` Christopher Friesen
2006-05-02 16:59 ` Andi Kleen
2006-05-02 17:07 ` Nick Piggin
2006-05-03 7:09 ` Mike Galbraith
2006-05-03 7:40 ` Andi Kleen [this message]
2006-05-03 9:11 ` Mike Galbraith
2006-05-03 9:16 ` Andi Kleen
2006-05-03 9:31 ` Mike Galbraith
2006-05-07 12:33 ` Nick Piggin
2006-05-07 12:43 ` Russell King
2006-05-07 12:56 ` Nick Piggin
2006-05-07 13:00 ` Nick Piggin
2006-05-07 13:18 ` Russell King
2006-05-07 13:30 ` Nick Piggin
2006-05-07 13:55 ` Russell King
2006-05-07 14:04 ` Nick Piggin
2006-05-07 16:03 ` Andi Kleen
2006-05-07 16:53 ` Russell King
2006-05-07 17:52 ` Mike Galbraith
2006-05-07 17:37 ` Mike Galbraith
2006-05-07 17:32 ` Mike Galbraith
2006-05-08 4:14 ` Mike Galbraith
2006-05-08 4:37 ` Mike Galbraith
2006-05-08 4:46 ` Nick Piggin
2006-05-08 5:24 ` Mike Galbraith
2006-05-08 5:30 ` Nick Piggin
2006-05-04 20:02 ` Florian Paul Schmidt
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