From: Alex Shi <alex.shi@linaro.org>
To: Frederic Weisbecker <fweisbec@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linaro Kernel <linaro-kernel@lists.linaro.org>,
Li Zhong <zhong@linux.vnet.ibm.com>
Subject: Re: nohz_full left a periodic tick cpu issue
Date: Thu, 12 Dec 2013 08:16:41 +0800 [thread overview]
Message-ID: <52A90069.4060401@linaro.org> (raw)
In-Reply-To: <20131211153114.GB7862@localhost.localdomain>
On 12/11/2013 11:31 PM, Frederic Weisbecker wrote:
>> > OK, I'll bite... Why not just use CONFIG_NO_HZ_FULL_SYSIDLE=y with
>> > CONFIG_NO_HZ_FULL_SYSIDLE_SMALL set to at least the number of CPUs on
>> > your system? The default for CONFIG_NO_HZ_FULL_SYSIDLE_SMALL is eight.
>> > This stuff is in mainline, though Frederic's exploitation of it is
>> > still in the works.
>> >
>> > On smaller systems, with Frederic's latest work, this should allow CPU 0
>> > to go idle quickly.
>> >
>> > What are you needing that this would not provide?
> Yeah I think that's what he needs, but we haven't much advertized that feature
> yet. I mean there are good reasons, it's not yet working :o)
Many thanks for Paul and Frederic's comments!
yes, I enabled FULL_SYSIDLE with FULL_SYSIDLE_SMALL=2, but as Frederic
said they are not yet working.
>
> But yeah Alex, I'm working on plugging the full system idle detection (CONFIG_NO_HZ_FULL_SYSIDLE=y)
> to shutdown the timekeeping CPUs adaptively.
>
> I have the patches ready, I'm just polishing a few things, writing changelogs, then I'll send
> to LKML with you Cc'ed :)
I am very glad to hear this. looking forward to seeing your patch soon. :)
--
Thanks
Alex
prev parent reply other threads:[~2013-12-12 0:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-11 6:28 nohz_full left a periodic tick cpu issue Alex Shi
2013-12-11 11:00 ` Alex Shi
2013-12-11 15:25 ` Paul E. McKenney
2013-12-11 15:31 ` Frederic Weisbecker
2013-12-12 0:16 ` Alex Shi [this message]
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