Messages in this thread | | | Date | Wed, 23 Jul 2014 11:21:54 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH] PM/CPU: Parallel enabling nonboot cpus with resume devices |
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On Wed, Jul 23, 2014 at 05:11:34PM +0800, Lan Tianyu wrote: > 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 waste cpu usage. > > To accelerate S3, this patches adds a new kernel configure > PM_PARALLEL_CPU_UP_FOR_SUSPEND to allow boot cpu to go forward to resume > devices after bringing up one nonboot cpu. The nonboot cpu will be in charge > of bringing up other cpus. This makes enabling cpu2~x parallel with resuming > devices. From the test result on 4 logical core laptop, the time of resume > device almost wasn't affected by enabling nonboot cpus lately while the start > point is almost 30ms earlier than before.
Why is this a CONFIG and why do we want to add more warts to the cpu hotplug instead of fixing it 'proper'?
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