From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Mike Galbraith <efault@gmx.de>
Cc: Andi Kleen <ak@suse.de>,
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: Mon, 08 May 2006 14:46:08 +1000 [thread overview]
Message-ID: <445ECD10.1090506@yahoo.com.au> (raw)
In-Reply-To: <1147063063.8809.7.camel@homer>
Mike Galbraith wrote:
>Sorry for yet another reply, but running the old starvation testcase
>that caused sched_clock() to be born in the first place tickled my
>funny-bone. With that running and hitting 300k context switches...
>
>now: 2100508962835 tick: 2100508972067 stamp: 2100508961220 total: 2906
>now: 2101531243883 tick: 2101531251877 stamp: 2101531238543 total: 2924
>now: 2102695422392 tick: 2102695431699 stamp: 2102695418265 total: 2940
>
>Accounting? Not :)
>
Yeah I agree with Andi that this accounting stuff is probably done
for some POSIX conformance that doesn't matter. Actually it is worse
than that because if anyone _really_ did need it, then they'll get a
horrible surprise when their system mysteriously fails in production.
It should either get ripped out, or perhaps converted to use jiffies
until a sane high resolution, low overhead scheme is developed (if
ever). And that would exclude something that does this accounting in
fastpaths for the 99.99% of processes that never use it.
--
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2006-05-08 4:46 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
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 [this message]
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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