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.
On Wednesday, October 08, 2014 10:54:41 PM Peter Zijlstra wrote:
> 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.
Agreed.
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
On 2014年10月09日 04:54, Peter Zijlstra wrote:
> 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.
>
Hi Peter:
Sorry, I don't know the gap of hotplug clearly. Could you elaborate it?
--
Best regards
Tianyu Lan
On 2014年10月09日 09:18, Lan Tianyu wrote:
> On 2014年10月09日 04:54, Peter Zijlstra wrote:
>> 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.
>>
>
> Hi Peter:
> Sorry, I don't know the gap of hotplug clearly. Could you elaborate it?
>
Hi Peter:
Could you elaborate the gap of hotplug? Thanks.
--
Best regards
Tianyu Lan