linux-kernel - Re: [PATCH v5 00/45] CPU hotplug: stop

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Date:	Fri, 15 Feb 2013 14:28:47 +0100
From:	Vincent Guittot <vincent.guittot@...aro.org>
To:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
Cc:	paulmck@...ux.vnet.ibm.com,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	linux-doc@...r.kernel.org, peterz@...radead.org,
	fweisbec@...il.com, linux-kernel@...r.kernel.org,
	walken@...gle.com, mingo@...nel.org, linux-arch@...r.kernel.org,
	xiaoguangrong@...ux.vnet.ibm.com, wangyun@...ux.vnet.ibm.com,
	nikunj@...ux.vnet.ibm.com, linux-pm@...r.kernel.org,
	Rusty Russell <rusty@...tcorp.com.au>, rostedt@...dmis.org,
	rjw@...k.pl, namhyung@...nel.org, tglx@...utronix.de,
	linux-arm-kernel@...ts.infradead.org, netdev@...r.kernel.org,
	oleg@...hat.com, sbw@....edu, tj@...nel.org,
	akpm@...ux-foundation.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v5 00/45] CPU hotplug: stop_machine()-free CPU hotplug

Hi Srivatsa,

I have run some tests with you branch (thanks Paul for the git tree)
and you will find results below.

The tests condition are:
- 5 CPUs system in 2 clusters
- The test plugs/unplugs CPU2 and it increases the system load each 20
plug/unplug sequence with either more cyclictests threads
- The test is done with all CPUs online and with only CPU0 and CPU2

The main conclusion is that there is no differences with and without
your patches with my stress tests. I'm not sure that it was the
expected results but the cpu_down is already quite low : 4-5ms in
average

I have attached the raw data to the mail

Regards,
Vincent


On 12 February 2013 04:58, Srivatsa S. Bhat
<srivatsa.bhat@...ux.vnet.ibm.com> wrote:
> On 02/12/2013 12:38 AM, Paul E. McKenney wrote:
>> On Mon, Feb 11, 2013 at 05:53:41PM +0530, Srivatsa S. Bhat wrote:
>>> On 02/11/2013 05:28 PM, Vincent Guittot wrote:
>>>> On 8 February 2013 19:09, Srivatsa S. Bhat
>>>> <srivatsa.bhat@...ux.vnet.ibm.com> wrote:
>>
>> [ . . . ]
>>
>>>>> Adding Vincent to CC, who had previously evaluated the performance and
>>>>> latency implications of CPU hotplug on ARM platforms, IIRC.
>>>>>
>>>>
>>>> Hi Srivatsa,
>>>>
>>>> I can try to run some of our stress tests on your patches.
>>>
>>> Great!
>>>
>>>> Have you
>>>> got a git tree that i can pull ?
>>>>
>>>
>>> Unfortunately, no, none at the moment..  :-(
>>
>> You do need to create an externally visible git tree.
>
> Ok, I'll do that soon.
>
>>  In the meantime,
>> I have added your series at rcu/bhat.2013.01.21a on -rcu:
>>
>> git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
>>
>> This should appear soon on a kernel.org mirror near you.  ;-)
>>
>
> Thank you very much, Paul! :-)
>
> Regards,
> Srivatsa S. Bhat
>

View attachment "test_load_5cpu_cyc_patched.txt" of type "text/plain" (70401 bytes)

View attachment "test_load_1cpu_cyc_patched.txt" of type "text/plain" (70401 bytes)

View attachment "test_load_5cpus_cyc_main.txt" of type "text/plain" (70401 bytes)

View attachment "test_load_1cpus_cyc_main.txt" of type "text/plain" (70401 bytes)