linux-kernel - Re: [RFC PATCH V3 0/3] PM/CPU: Parallel enalbing nonboot cpus with resume devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 09 Oct 2014 09:18:45 +0800
From:	Lan Tianyu <tianyu.lan@...el.com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	mingo@...nel.org, rafael.j.wysocki@...el.com, toshi.kani@...com,
	akpm@...ux-foundation.org, ktkhai@...allels.com, fabf@...net.be,
	laijs@...fujitsu.com, srivatsa.bhat@...ux.vnet.ibm.com,
	ego@...ux.vnet.ibm.com, srivatsa@....edu, viresh.kumar@...aro.org,
	todd.e.brandt@...ux.intel.com, tipbot@...or.com,
	wangyun@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [RFC PATCH V3 0/3] PM/CPU: Parallel enalbing nonboot cpus with
 resume devices

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/