From: Nigel Cunningham <ncunningham@crca.org.au>
To: Dominik Brodowski <linux@dominikbrodowski.net>,
Nigel Cunningham <nigel@tuxonice.net>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Arjan van de Ven <arjan@linux.jf.intel.com>,
Venkatesh Pallipadi <venki@google.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
ego@in.ibm.com, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch 0/7] sched: change nohz idle load balancing logic to push model
Date: Thu, 20 May 2010 21:35:47 +1000 [thread overview]
Message-ID: <4BF51E93.4030601@crca.org.au> (raw)
In-Reply-To: <20100520111753.GA2264@isilmar-3.linta.de>
Hi.
On 20/05/10 21:17, Dominik Brodowski wrote:
> Hey,
>
> On Thu, May 20, 2010 at 09:07:42PM +1000, Nigel Cunningham wrote:
>> "Load balancing tick" is still number one in my powertop list of top
>> causes of wakeups (sitting at ~60 to 80 per second as I type this, with
>> ~170 wakeups per second total). Comparing this to the numbers I posted
>> earlier, we seem to have a win.
>>
>> I do wonder, though, whether further work could still be done. If I take
>> one core offline, for example, I'm still getting load balancing ticks.
>> Intuitively, I'd expect there to be no need for them with only one core
>> available. But maybe I'm just ignorant of what's going on.
>
> Are you using HZ=1000, and is the CPU active ~ 6-8 % ? If so, is it just the
> regular timer tick while the CPU is active, and so not a real "wakeup"? (Or
> possibly double the number if both CPUs are active)
HZ is 1000, and the CPU running percentage in Powertop is low (2% when
I'm not typing).
Regards,
Nigel
next prev parent reply other threads:[~2010-05-20 11:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-17 18:27 [patch 0/7] sched: change nohz idle load balancing logic to push model Suresh Siddha
2010-05-17 18:27 ` [patch 1/7] softirq: Add a no local fallback option to send_remote_softirq Suresh Siddha
2010-05-17 18:27 ` [patch 2/7] softirq: add init_remote_softirq_csd() Suresh Siddha
2010-05-17 18:27 ` [patch 3/7] softirq: avoid softirq_work_list for SCHED_SOFTIRQ when sent remotely Suresh Siddha
2010-05-20 8:12 ` Peter Zijlstra
2010-05-20 8:14 ` David Miller
2010-05-20 8:23 ` Jens Axboe
2010-05-20 8:29 ` Peter Zijlstra
2010-05-20 9:18 ` David Miller
2010-05-17 18:27 ` [patch 4/7] sched: Change nohz ilb logic from pull to push model Suresh Siddha
2010-06-01 23:47 ` Vaidyanathan Srinivasan
2010-06-02 22:27 ` Suresh Siddha
2010-05-17 18:27 ` [patch 5/7] sched: Change select_nohz_load_balancer to return void Suresh Siddha
2010-05-17 18:27 ` [patch 6/7] sched: change nohz.load_balancer to be nr_cpu_ids based Suresh Siddha
2010-05-20 9:49 ` Peter Zijlstra
2010-05-17 18:27 ` [patch 7/7] timers: use nearest busy cpu for migrating timers from an idle cpu Suresh Siddha
2010-06-01 23:37 ` Vaidyanathan Srinivasan
2010-06-02 22:02 ` Suresh Siddha
2010-05-17 22:39 ` [patch 0/7] sched: change nohz idle load balancing logic to push model Nigel Cunningham
2010-05-19 9:19 ` Dominik Brodowski
2010-05-20 10:50 ` Peter Zijlstra
2010-05-22 0:09 ` Suresh Siddha
2010-05-31 9:17 ` Peter Zijlstra
2010-06-09 10:13 ` [tip:sched/core] sched: Change " tip-bot for Venkatesh Pallipadi
2010-05-20 11:07 ` [patch 0/7] sched: change " Nigel Cunningham
2010-05-20 11:17 ` Dominik Brodowski
2010-05-20 11:35 ` Nigel Cunningham [this message]
2010-05-20 12:13 ` Dominik Brodowski
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