From: Olivier Langlois <olivier@trillion01.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@redhat.com, tglx@linutronix.de, fweisbec@gmail.com,
schwidefsky@de.ibm.com, rostedt@goodmis.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] process cputimer is moving faster than its corresponding clock
Date: Sun, 14 Apr 2013 21:55:09 -0400 [thread overview]
Message-ID: <1365990909.29519.6.camel@Wailaba2> (raw)
In-Reply-To: <1365758166.17140.35.camel@laptop>
On Fri, 2013-04-12 at 11:16 +0200, Peter Zijlstra wrote:
> On Wed, 2013-04-10 at 11:48 -0400, Olivier Langlois wrote:
> > Please explain how expensive it is. All I am seeing is a couple of
> > additions.
>
> Let me start with this, since your earlier argument also refers to
> this.
>
> So yes it does look simple and straight fwd, only one addition. However
> its an atomic operation across all threads of the same process. Imagine
> a single process with 512 threads, all running on a separate cpu.
>
Peter,
It now makes perfect sense. Thank you for your explanation. It is
showing me an aspect that I did overlook.
Greetings,
next prev parent reply other threads:[~2013-04-15 1:55 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-05 17:59 [PATCH] process cputimer is moving faster than its corresponding clock Olivier Langlois
2013-04-10 11:35 ` Peter Zijlstra
2013-04-10 15:48 ` Olivier Langlois
2013-04-12 9:16 ` Peter Zijlstra
2013-04-15 1:55 ` Olivier Langlois [this message]
2013-04-12 9:18 ` Peter Zijlstra
2013-04-12 10:50 ` Peter Zijlstra
2013-04-12 15:55 ` Peter Zijlstra
2013-04-15 6:11 ` Olivier Langlois
2013-04-19 13:03 ` Frederic Weisbecker
2013-04-19 17:38 ` KOSAKI Motohiro
2013-04-19 18:08 ` KOSAKI Motohiro
2013-04-26 4:40 ` Olivier Langlois
2013-04-26 6:27 ` Olivier Langlois
2013-04-26 19:08 ` KOSAKI Motohiro
2013-04-27 1:51 ` Olivier Langlois
2013-04-27 2:15 ` KOSAKI Motohiro
2013-04-27 5:02 ` Olivier Langlois
2013-04-27 5:17 ` Olivier Langlois
2013-04-27 5:31 ` Olivier Langlois
2013-04-27 5:06 ` Olivier Langlois
2013-04-27 4:40 ` [PATCH v2 1/3] " Olivier Langlois
2013-04-29 0:45 ` Frederic Weisbecker
2013-04-29 17:29 ` Olivier Langlois
2013-04-29 5:06 ` KOSAKI Motohiro
2013-04-29 17:10 ` Olivier Langlois
2013-04-29 17:41 ` Olivier Langlois
2013-04-29 17:56 ` KOSAKI Motohiro
2013-04-29 18:20 ` Olivier Langlois
2013-04-29 18:31 ` KOSAKI Motohiro
2013-04-29 18:54 ` Olivier Langlois
2013-04-29 19:09 ` KOSAKI Motohiro
2013-04-29 21:20 ` Olivier Langlois
2013-04-29 22:42 ` KOSAKI Motohiro
[not found] ` <1367036552.7911.63.camel@Wailaba2>
2013-04-27 4:40 ` [PATCH v2 2/3] " Olivier Langlois
2013-04-27 4:41 ` [PATCH v2 3/3] " Olivier Langlois
2013-04-29 6:25 ` KOSAKI Motohiro
2013-04-29 17:16 ` Olivier Langlois
2013-04-11 3:29 ` [PATCH] " Olivier Langlois
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