From: Andrew Paprocki <andrew@ishiboo.com>
To: linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/1]: timers: Timer Migration
Date: Wed, 17 Sep 2008 07:35:04 +0000 (UTC) [thread overview]
Message-ID: <loom.20080917T072423-185@post.gmane.org> (raw)
In-Reply-To: 1221566730.6943.16.camel@lappy.programming.kicks-ass.net
Peter Zijlstra <a.p.zijlstra <at> chello.nl> writes:
> This seems like an exceedingly dumb idea - cpu 0 might be a long long
> way from x and by pushing all timers to cpu0 you might actually overload
> cpu 0.
You have to give credit to Solaris for doing that first :). They implemented
usleep() using nanosleep() which uses the kernel callout queue. That queue is
single threaded and only processed on CPU0 in the clock interrupt handler,
causing CPU0 to spin 100% if enough calls to usleep() are made across the system.
http://bugs.opensolaris.org/view_bug.do?bug_id=6565503
-Andrew
next prev parent reply other threads:[~2008-09-17 7:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-16 9:12 [RFC PATCH 0/1]: timers: Timer Migration Arun R Bharadwaj
2008-09-16 12:05 ` Peter Zijlstra
2008-09-16 16:47 ` Arun Bharadwaj
2008-09-17 7:35 ` Andrew Paprocki [this message]
2008-09-16 12:49 ` Andi Kleen
2008-09-16 13:53 ` Arjan van de Ven
2008-09-17 5:01 ` Arun R Bharadwaj
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