From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Tejun Heo <tj@kernel.org>
Cc: peterz@infradead.org, fweisbec@gmail.com, oleg@redhat.com,
walken@google.com, mingo@kernel.org, linux-arch@vger.kernel.org,
vincent.guittot@linaro.org, xiaoguangrong@linux.vnet.ibm.com,
wangyun@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com,
nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org,
rusty@rustcorp.com.au, Steven Rostedt <rostedt@goodmis.org>,
namhyung@kernel.org, tglx@linutronix.de, laijs@cn.fujitsu.com,
zhong@linux.vnet.ibm.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, sbw@mit.edu,
David Laight <David.Laight@ACULAB.COM>,
akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 15/45] rcu: Use get/put_online_cpus_atomic() to prevent CPU offline
Date: Wed, 26 Jun 2013 23:52:17 +0530 [thread overview]
Message-ID: <51CB3159.8000509@linux.vnet.ibm.com> (raw)
In-Reply-To: <20130626152148.GA4405@mtj.dyndns.org>
On 06/26/2013 08:51 PM, Tejun Heo wrote:
> On Wed, Jun 26, 2013 at 10:51:11AM -0400, Steven Rostedt wrote:
>>> It would also increase the latency of CPU-hotunplug operations.
>>
>> Is that a big deal?
>
> I thought that was the whole deal with this patchset - making cpu
> hotunplugs lighter and faster mostly for powersaving. That said, just
> removing stop_machine call would be a pretty good deal and I don't
> know how meaningful reducing CPU hotunplug latency is. Srivatsa?
>
Keeping the hotunplug latency is important for suspend/resume, where
we take all non-boot CPUs in a loop. That's an interesting use-case
where intrusiveness doesn't matter much, but latency does. So yes,
making CPU hotplug faster is also one of the goals of this patchset.
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2013-06-26 18:25 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-25 20:25 [PATCH v2 00/45] CPU hotplug: stop_machine()-free CPU hotplug, part 1 Srivatsa S. Bhat
2013-06-25 20:25 ` [PATCH v2 01/45] CPU hotplug: Provide APIs to prevent CPU offline from atomic context Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 02/45] CPU hotplug: Clarify the usage of different synchronization APIs Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 03/45] Documentation, CPU hotplug: Recommend usage of get/put_online_cpus_atomic() Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 04/45] CPU hotplug: Add infrastructure to check lacking hotplug synchronization Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 05/45] CPU hotplug: Protect set_cpu_online() to avoid false-positives Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 06/45] CPU hotplug: Sprinkle debugging checks to catch locking bugs Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 07/45] CPU hotplug: Expose the new debug config option Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 08/45] CPU hotplug: Convert preprocessor macros to static inline functions Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 09/45] smp: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 10/45] sched/core: " Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 11/45] migration: Use raw_spin_lock/unlock since interrupts are already disabled Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 12/45] sched/fair: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 13/45] timer: " Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 14/45] sched/rt: " Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 15/45] rcu: " Srivatsa S. Bhat
2013-06-25 22:00 ` Paul E. McKenney
2013-06-26 14:09 ` Srivatsa S. Bhat
2013-06-26 14:29 ` David Laight
2013-06-26 14:34 ` Paul E. McKenney
2013-06-26 14:51 ` Steven Rostedt
2013-06-26 15:21 ` Tejun Heo
2013-06-26 15:33 ` Steven Rostedt
2013-06-26 17:29 ` Tejun Heo
2013-06-26 18:28 ` Srivatsa S. Bhat
2013-06-26 21:34 ` Tejun Heo
2013-06-27 6:53 ` Srivatsa S. Bhat
2013-06-26 18:22 ` Srivatsa S. Bhat [this message]
2013-06-27 8:54 ` David Laight
2013-06-27 10:06 ` Srivatsa S. Bhat
2013-06-26 14:45 ` Paul E. McKenney
2013-06-26 18:18 ` Srivatsa S. Bhat
2013-06-26 14:33 ` Paul E. McKenney
2013-06-25 20:28 ` [PATCH v2 16/45] tick-broadcast: " Srivatsa S. Bhat
2013-06-25 20:28 ` [PATCH v2 17/45] time/clocksource: " Srivatsa S. Bhat
2013-06-25 20:28 ` [PATCH v2 18/45] softirq: " Srivatsa S. Bhat
2013-06-25 20:28 ` [PATCH v2 19/45] irq: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 20/45] net: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 21/45] block: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 22/45] percpu_counter: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 23/45] infiniband: ehca: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 24/45] [SCSI] fcoe: " Srivatsa S. Bhat
2013-06-25 20:30 ` [PATCH v2 25/45] staging/octeon: " Srivatsa S. Bhat
2013-06-25 20:45 ` Greg Kroah-Hartman
2013-06-25 20:30 ` [PATCH v2 26/45] x86: " Srivatsa S. Bhat
2013-06-25 20:30 ` [PATCH v2 27/45] perf/x86: " Srivatsa S. Bhat
2013-06-25 20:30 ` [PATCH v2 28/45] KVM: " Srivatsa S. Bhat
2013-06-26 8:20 ` Paolo Bonzini
2013-06-25 20:30 ` [PATCH v2 29/45] kvm/vmx: " Srivatsa S. Bhat
2013-06-26 7:46 ` Paolo Bonzini
2013-06-26 8:06 ` Srivatsa S. Bhat
2013-06-26 8:23 ` Paolo Bonzini
2013-06-26 8:41 ` Srivatsa S. Bhat
2013-06-26 8:57 ` Paolo Bonzini
2013-06-25 20:30 ` [PATCH v2 30/45] x86/xen: " Srivatsa S. Bhat
2013-06-25 20:31 ` [PATCH v2 31/45] alpha/smp: " Srivatsa S. Bhat
2013-06-25 20:31 ` [PATCH v2 32/45] blackfin/smp: " Srivatsa S. Bhat
2013-06-25 20:31 ` [PATCH v2 33/45] cris/smp: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 34/45] hexagon/smp: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 35/45] ia64: irq, perfmon: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 36/45] ia64: smp, tlb: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 37/45] m32r: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 38/45] MIPS: " Srivatsa S. Bhat
2013-06-26 13:39 ` Ralf Baechle
2013-06-27 7:08 ` Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 39/45] mn10300: " Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 40/45] powerpc, irq: Use GFP_ATOMIC allocations in atomic context Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 41/45] powerpc: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 42/45] powerpc: Use get/put_online_cpus_atomic() to avoid false-positive warning Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 43/45] sh: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 44/45] sparc: " Srivatsa S. Bhat
2013-06-25 20:34 ` [PATCH v2 45/45] tile: " Srivatsa S. Bhat
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