From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Arjan van de Ven" <arjan@linux.intel.com>,
"Fernando Luis Vázquez Cao" <fernando_b1@lab.ntt.co.jp>,
"Frederic Weisbecker" <fweisbec@gmail.com>,
"Ingo Molnar" <mingo@kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
"Tetsuo Handa" <penguin-kernel@I-love.SAKURA.ne.jp>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock
Date: Wed, 21 Aug 2013 18:41:46 +0200 [thread overview]
Message-ID: <20130821164146.GA15194@redhat.com> (raw)
In-Reply-To: <20130821142356.GC31370@twins.programming.kicks-ass.net>
On 08/21, Peter Zijlstra wrote:
>
> The other consideration is that this adds two branches to the normal
> schedule path. I really don't know what the regular ratio between
> schedule() and io_schedule() is -- and I suspect it can very much depend
> on workload -- but it might be a net loss due to that, even if it makes
> io_schedule() 'lots' cheaper.
Yes, agreed. Please ignore it for now, I didn't try to actually suggest
this change. And even if this is fine perfomance wise, this needs some
benchmarking.
Well. actually I have a vague feeling that _perhaps_ this change can
help to solve other problems we are discussing, but I am not sure and
right now I can't even explain the idea to me.
In short: please ignore ;)
Oleg.
next prev parent reply other threads:[~2013-08-21 16:48 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-16 15:42 [PATCH RESEND 0/4] nohz: Fix racy sleeptime stats Frederic Weisbecker
2013-08-16 15:42 ` [PATCH 1/4] nohz: Only update sleeptime stats locally Frederic Weisbecker
2013-08-18 16:49 ` Oleg Nesterov
2013-08-18 21:38 ` Frederic Weisbecker
2013-08-18 17:04 ` Oleg Nesterov
2013-08-19 18:05 ` Stratos Karafotis
2013-08-16 15:42 ` [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock Frederic Weisbecker
2013-08-16 16:02 ` Oleg Nesterov
2013-08-16 16:20 ` Frederic Weisbecker
2013-08-16 16:26 ` Oleg Nesterov
2013-08-16 16:46 ` Frederic Weisbecker
2013-08-16 16:49 ` Oleg Nesterov
2013-08-16 17:12 ` Frederic Weisbecker
2013-08-18 16:36 ` Oleg Nesterov
2013-08-18 21:25 ` Frederic Weisbecker
2013-08-19 10:58 ` Peter Zijlstra
2013-08-19 15:44 ` Arjan van de Ven
2013-08-19 15:47 ` Arjan van de Ven
2013-08-19 11:10 ` Peter Zijlstra
2013-08-19 11:15 ` Peter Zijlstra
2013-08-20 6:59 ` Fernando Luis Vázquez Cao
2013-08-20 8:44 ` Peter Zijlstra
2013-08-20 15:29 ` Frederic Weisbecker
2013-08-20 15:33 ` Arjan van de Ven
2013-08-20 15:35 ` Frederic Weisbecker
2013-08-20 15:41 ` Arjan van de Ven
2013-08-20 15:31 ` Arjan van de Ven
2013-08-20 16:01 ` Peter Zijlstra
2013-08-20 16:33 ` Oleg Nesterov
2013-08-20 17:54 ` Peter Zijlstra
2013-08-20 18:25 ` Oleg Nesterov
2013-08-21 8:31 ` Peter Zijlstra
2013-08-21 11:35 ` Oleg Nesterov
2013-08-21 12:33 ` Peter Zijlstra
2013-08-21 14:23 ` Peter Zijlstra
2013-08-21 16:41 ` Oleg Nesterov [this message]
2013-10-01 14:05 ` Frederic Weisbecker
2013-10-01 14:26 ` Frederic Weisbecker
2013-10-01 14:27 ` Frederic Weisbecker
2013-10-01 14:49 ` Frederic Weisbecker
2013-10-01 15:00 ` Peter Zijlstra
2013-10-01 15:21 ` Frederic Weisbecker
2013-10-01 15:56 ` Peter Zijlstra
2013-10-01 16:47 ` Frederic Weisbecker
2013-10-01 16:59 ` Peter Zijlstra
2013-10-02 12:45 ` Frederic Weisbecker
2013-10-02 12:50 ` Peter Zijlstra
2013-10-02 14:35 ` Arjan van de Ven
2013-10-02 16:01 ` Frederic Weisbecker
2013-08-21 12:48 ` Peter Zijlstra
2013-08-21 17:09 ` Oleg Nesterov
2013-08-21 18:31 ` Peter Zijlstra
2013-08-21 18:32 ` Oleg Nesterov
2013-08-20 22:18 ` Frederic Weisbecker
2013-08-21 11:49 ` Oleg Nesterov
2013-08-20 6:21 ` Fernando Luis Vázquez Cao
2013-08-20 21:55 ` Frederic Weisbecker
2013-08-16 16:32 ` Frederic Weisbecker
2013-08-16 16:33 ` Oleg Nesterov
2013-08-16 16:49 ` Frederic Weisbecker
2013-08-16 16:37 ` Frederic Weisbecker
2013-08-18 16:54 ` Oleg Nesterov
2013-08-18 21:40 ` Frederic Weisbecker
2013-08-16 15:42 ` [PATCH 3/4] nohz: Consolidate sleep time stats read code Frederic Weisbecker
2013-08-18 17:00 ` Oleg Nesterov
2013-08-18 21:47 ` Frederic Weisbecker
2013-08-16 15:42 ` [PATCH 4/4] nohz: Convert a few places to use local per cpu accesses Frederic Weisbecker
2013-08-16 16:00 ` Peter Zijlstra
2013-08-16 16:12 ` Frederic Weisbecker
2013-08-16 16:19 ` Oleg Nesterov
2013-08-16 16:34 ` Frederic Weisbecker
2013-08-20 18:15 ` [PATCH RESEND 0/4] nohz: Fix racy sleeptime stats Oleg Nesterov
2013-08-21 8:28 ` Peter Zijlstra
2013-08-21 11:42 ` Oleg Nesterov
-- strict thread matches above, loose matches on Subject: below --
2014-05-07 13:41 [PATCH 1/4] nohz: Only update sleeptime stats locally Denys Vlasenko
2014-05-07 13:41 ` [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock Denys Vlasenko
2014-04-24 18:45 [PATCH 1/4] nohz: Only update sleeptime stats locally Denys Vlasenko
2014-04-24 18:45 ` [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock Denys Vlasenko
2013-08-09 0:54 [PATCH 0/4] nohz: Fix racy sleeptime stats Frederic Weisbecker
2013-08-09 0:54 ` [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock Frederic Weisbecker
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