Messages in this thread | | | Date | Wed, 23 Jul 2014 17:48:52 +0800 | From | Lan Tianyu <> | Subject | Re: [RFC PATCH] PM/CPU: Parallel enabling nonboot cpus with resume devices |
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On 2014年07月23日 17:21, Peter Zijlstra wrote: > 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'? >
Hi Peter: Thank you for your review. Because I just tested this patch on x86 platform and didn't want to cause some regressions on the other platforms. So I made it as a new CONFIG. In theory, this should not cause some problems. If none objects, it can be the default behavior.
-- Best regards Tianyu Lan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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