From: Peter Zijlstra <peterz@infradead.org>
To: Lan Tianyu <tianyu.lan@intel.com>
Cc: mingo@kernel.org, rafael.j.wysocki@intel.com, toshi.kani@hp.com,
akpm@linux-foundation.org, ktkhai@parallels.com, fabf@skynet.be,
laijs@cn.fujitsu.com, srivatsa.bhat@linux.vnet.ibm.com,
ego@linux.vnet.ibm.com, srivatsa@mit.edu,
viresh.kumar@linaro.org, todd.e.brandt@linux.intel.com,
tipbot@zytor.com, wangyun@linux.vnet.ibm.com,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC PATCH V3 0/3] PM/CPU: Parallel enalbing nonboot cpus with resume devices
Date: Wed, 8 Oct 2014 22:54:41 +0200 [thread overview]
Message-ID: <20141008205441.GJ4750@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <1411633925-9018-1-git-send-email-tianyu.lan@intel.com>
On Thu, Sep 25, 2014 at 04:32:02PM +0800, Lan Tianyu wrote:
> This patchset is to parallel enabling nonboot cpus with resuming devices
> during system resume in order to accelerate S2RAM. From test result on
> a 8 logical core Haswell machine, system resume time reduces from 347ms
> to 217ms with this patchset.
>
> In the current world, all nonboot cpus are enabled serially during system
> resume. System resume sequence is that boot cpu enables nonboot cpu one by
> one and then resume devices. Before resuming devices, there are few tasks
> assigned to nonboot cpus after they are brought up. This wastes cpu usage.
>
> This patchset is to allow boot cpu to go forward to resume devices after
> bringing up one nonboot cpu and starting a thread. The thread will be in
> charge of bringing up other frozen cpus. The thread will be scheduled to
> the first online cpu to run . This makes enabling cpu2~x parallel with
> resuming devices.
So I feel we should really clean up hotplug before doing anything like
this. Its a trainwreck and just piling more and more hacks ontop isn't
going to help any.
next prev parent reply other threads:[~2014-10-08 20:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-25 8:32 [RFC PATCH V3 0/3] PM/CPU: Parallel enalbing nonboot cpus with resume devices Lan Tianyu
2014-09-25 8:32 ` [RFC PATCH V3 1/3] " Lan Tianyu
2014-09-25 8:32 ` [RFC PATCH V2 2/3] X86/CPU: Initialize MTRR/PAT when each cpu is online during system resume Lan Tianyu
2014-09-25 8:32 ` [RFC PATCH V3 3/3] Cpufreq: Hold cpu_add_remove_lock before change cpufreq_suspended flag Lan Tianyu
2014-10-08 20:54 ` Peter Zijlstra [this message]
2014-10-08 22:01 ` [RFC PATCH V3 0/3] PM/CPU: Parallel enalbing nonboot cpus with resume devices Rafael J. Wysocki
2014-10-09 1:18 ` Lan Tianyu
2014-10-22 6:06 ` Lan Tianyu
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