Messages in this thread | | | Date | Wed, 8 Oct 2014 22:54:41 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH V3 0/3] PM/CPU: Parallel enalbing nonboot cpus with resume devices |
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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.
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