From: Kevin Hilman <khilman@linaro.org>
To: paulmck@linux.vnet.ibm.com
Cc: Christoph Lameter <cl@linux.com>,
Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Rob Landley <rob@landley.net>,
linux-kernel@vger.kernel.org, josh@joshtriplett.org,
zhong@linux.vnet.ibm.com, geoff@infradead.org,
tglx@linutronix.de
Subject: Re: [PATCH] nohz1: Documentation
Date: Fri, 22 Mar 2013 12:01:12 -0700 [thread overview]
Message-ID: <87ehf7b6o7.fsf@linaro.org> (raw)
In-Reply-To: <20130321185821.GF3637@linux.vnet.ibm.com> (Paul E. McKenney's message of "Thu, 21 Mar 2013 11:58:21 -0700")
[...]
>> >
>> > In the meantime, one approach is to bind all these SCHED_OTHER tasks
>> > to designated housekeeping CPU(s) that don't run your main workload.
>>
>> One cannot bind kevent threads and other per cpu threads to another
>> processor. So right now there is no way to avoid this issue.
>
> Yep, my approach works only for those threads that are free to migrate.
> Of course, in some cases, you can avoid per-CPU threads running by pinning
> interrupts, avoiding certain operations in your workload, and so on.
Speaking of threads that are not free to migrate, you might add a bit to
the doc explaining that these various kernel threads that cannot migrate
are also potential sources of jitter and also reasons why a CPU may exit
(or not enter) full nohz mode.
And thanks a ton for writing up this detailed doc. Speaking as someone
trying to get full nohz working on a new arch (ARM), getting my head
around all of this has been challenging, and your doc is a great help.
Kevin
next prev parent reply other threads:[~2013-03-22 19:01 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-18 16:29 Paul E. McKenney
2013-03-18 18:13 ` Rob Landley
2013-03-18 18:46 ` Frederic Weisbecker
2013-03-18 19:59 ` Rob Landley
2013-03-18 20:48 ` Frederic Weisbecker
2013-03-18 22:25 ` Paul E. McKenney
2013-03-20 23:32 ` Steven Rostedt
2013-03-20 23:55 ` Paul E. McKenney
2013-03-21 0:27 ` Steven Rostedt
2013-03-21 2:22 ` Paul E. McKenney
2013-03-21 10:16 ` Borislav Petkov
2013-03-21 15:18 ` Paul E. McKenney
2013-03-21 16:00 ` Borislav Petkov
2013-03-21 15:45 ` Arjan van de Ven
2013-03-21 17:18 ` Paul E. McKenney
2013-03-21 17:41 ` Arjan van de Ven
2013-03-21 18:02 ` Paul E. McKenney
2013-03-22 18:37 ` Kevin Hilman
2013-03-22 19:25 ` Paul E. McKenney
2013-03-22 4:59 ` Rob Landley
2013-03-21 18:01 ` Frederic Weisbecker
2013-03-21 18:26 ` Paul E. McKenney
2013-03-21 16:08 ` Christoph Lameter
2013-03-21 17:15 ` Paul E. McKenney
2013-03-21 18:39 ` Christoph Lameter
2013-03-21 18:58 ` Paul E. McKenney
2013-03-21 20:04 ` Christoph Lameter
2013-03-21 20:42 ` Frederic Weisbecker
2013-03-21 21:02 ` Christoph Lameter
2013-03-21 21:06 ` Frederic Weisbecker
2013-03-21 20:50 ` Paul E. McKenney
2013-03-22 14:38 ` Christoph Lameter
2013-03-22 16:28 ` Paul E. McKenney
2013-03-25 14:31 ` Christoph Lameter
2013-03-25 14:37 ` Frederic Weisbecker
2013-03-25 15:18 ` Christoph Lameter
2013-03-25 15:20 ` Frederic Weisbecker
2013-03-22 9:52 ` Mats Liljegren
2013-03-22 19:01 ` Kevin Hilman [this message]
2013-03-21 18:44 ` Steven Rostedt
2013-03-21 18:53 ` Christoph Lameter
2013-03-21 19:16 ` Steven Rostedt
2013-03-21 18:59 ` Paul E. McKenney
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