From: Olivier Langlois <olivier@trillion01.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Chris Metcalf <cmetcalf@tilera.com>,
Christoph Lameter <cl@linux.com>,
Geoff Levand <geoff@infradead.org>,
Gilad Ben Yossef <gilad@benyossef.com>,
Hakan Akkan <hakanakkan@gmail.com>,
Kevin Hilman <khilman@linaro.org>,
Li Zhong <zhong@linux.vnet.ibm.com>,
Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 2/3] posix_timers: Defer per process timer stop after timers processing
Date: Tue, 30 Apr 2013 13:51:58 -0400 [thread overview]
Message-ID: <1367344318.8833.59.camel@Wailaba2> (raw)
In-Reply-To: <20130430125423.GB8272@somewhere>
>
> > Maybe the condition around the posix_cpu_timer_schedule() block inside
> > cpu_timer_fire() could even be a good candidate for 'unlikely'
> > qualifier.
>
> Well, cpu_timer_fire() is probably not a fast path. So helping branch
> prediction there probably won't have much measurable effect in practice.
>
Frederic, I'm totally sure that you are right on the measurable effect.
When I did propose the 'unlikely' qualifier, please note, that I also
had a documentary purpose in mind.
Would you have searched the 'likely' path that does
posix_cpu_timer_schedule() when you did modify the code if the
'unlikely' tag would have been present?
Greetings,
Olivier
next prev parent reply other threads:[~2013-04-30 17:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-18 17:23 [RFC GIT PULL] nohz: Posix cpu timers handling on full dynticks Frederic Weisbecker
2013-04-18 17:23 ` [PATCH 1/3] nohz: New APIs to re-evaluate the tick on full dynticks CPUs Frederic Weisbecker
2013-04-18 17:23 ` [PATCH 2/3] posix_timers: Defer per process timer stop after timers processing Frederic Weisbecker
2013-04-19 4:30 ` Olivier Langlois
2013-04-19 12:47 ` Frederic Weisbecker
2013-04-26 4:27 ` Olivier Langlois
2013-04-26 6:21 ` Olivier Langlois
2013-04-30 12:54 ` Frederic Weisbecker
2013-04-30 17:51 ` Olivier Langlois [this message]
2013-05-06 23:03 ` Frederic Weisbecker
2013-04-18 17:23 ` [PATCH 3/3] posix_timers: Kick full dynticks CPUs when a posix cpu timer is armed Frederic Weisbecker
2013-04-19 12:51 ` [RFC GIT PULL] nohz: Posix cpu timers handling on full dynticks Frederic Weisbecker
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