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From: Andrew Morton <akpm@linux-foundation.org>
To: Gautham R Shenoy <ego@in.ibm.com>
Cc: linux-kernel@vger.kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Balbir Singh <balbir@in.ibm.com>,
	Rusty Russel <rusty@rustcorp.com.au>,
	Paul E McKenney <paulmck@us.ibm.com>,
	Nathan Lynch <ntl@pobox.com>, Ingo Molnar <mingo@elte.hu>,
	Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>,
	Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
	Dipankar Sarma <dipankar@in.ibm.com>,
	Shoahua Li <shaohua.li@linux.com>
Subject: Re: [RFD PATCH 0/4] cpu: Bulk CPU Hotplug support.
Date: Mon, 15 Jun 2009 23:23:18 -0700	[thread overview]
Message-ID: <20090615232318.74b099a6.akpm@linux-foundation.org> (raw)
In-Reply-To: <20090616053431.30891.18682.stgit@sofia.in.ibm.com>

On Tue, 16 Jun 2009 11:08:39 +0530 Gautham R Shenoy <ego@in.ibm.com> wrote:

> Currently on a ppc64 box with 16 CPUs, the time taken for
> a individual cpu-hotplug operation is as follows.
> 
> 	# time echo 0 > /sys/devices/system/cpu/cpu2/online
> 	real    0m0.025s
> 	user    0m0.000s
> 	sys     0m0.002s
> 
> 	# time echo 1 > /sys/devices/system/cpu/cpu2/online
> 	real    0m0.021s
> 	user    0m0.000s
> 	sys     0m0.000s

Surprised.  Do people really online and offline CPUs frequently enough
for this to be a problem?


  parent reply	other threads:[~2009-06-16  6:24 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-16  5:38 [RFD PATCH 0/4] cpu: Bulk CPU Hotplug support Gautham R Shenoy
2009-06-16  5:38 ` [RFD PATCH 1/4] powerpc: cpu: Reduce the polling interval in __cpu_up() Gautham R Shenoy
2009-06-16 16:06   ` Nathan Lynch
2009-06-16 16:37     ` Gautham R Shenoy
2009-06-16  5:38 ` [RFD PATCH 2/4] cpu: sysfs interface for hotplugging bunch of CPUs Gautham R Shenoy
2009-06-16 16:22   ` Nathan Lynch
2009-06-16 16:33     ` Gautham R Shenoy
2009-06-16  5:38 ` [RFD PATCH 3/4] cpu: Define new functions cpu_down_mask and cpu_up_mask Gautham R Shenoy
2009-06-16  5:38 ` [RFD PATCH 4/4] cpu: measure time taken by subsystem notifiers during cpu-hotplug Gautham R Shenoy
2009-06-16  6:23 ` Andrew Morton [this message]
2009-06-16  8:07   ` [RFD PATCH 0/4] cpu: Bulk CPU Hotplug support Vaidyanathan Srinivasan
2009-06-16 21:00     ` Paul E. McKenney
2009-06-24 15:02       ` Pavel Machek
2009-06-17  7:32     ` Peter Zijlstra
2009-06-17  7:40       ` Balbir Singh
2009-06-17 14:38       ` Paul E. McKenney
2009-06-17 15:07         ` Ingo Molnar
2009-06-17 20:26           ` Peter Zijlstra
2009-06-20 15:35             ` Ingo Molnar
2009-06-22  6:08               ` Nathan Lynch
2009-06-17 13:50 ` Suresh Siddha

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