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Re: [RFC PATCH] alispinlock: acceleration from lock integration on multi-core platform

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  Re: [RFC PATCH] alispinlock: acceleration from lock integration on  multi-core platform Ling Ma <ling.ma.program@gmail.com> - 2016-01-19 10:00 +0100
    Re: [RFC PATCH] alispinlock: acceleration from lock integration on  multi-core platform Waiman Long <waiman.long@hpe.com> - 2016-01-19 16:40 +0100

#1312017 — Re: [RFC PATCH] alispinlock: acceleration from lock integration on multi-core platform

Is it acceptable for performance improvement or more comments on this patch?

Thanks
Ling

2016-01-14 16:10 GMT+08:00 Ling Ma <ling.ma.program@gmail.com>:
> Alan,
>
> The attachment  (alispinlock.tar.bz2) in last email includes our
> sample cases for spinlock.
> The attachment (lock_test.tar.bz2) in this email includes the patch on
> kernel 4.3v ,
> which has been applied to actual real kernel locks:
> when we run the user space program (thread.c) on 72cores E5-2699v3,
> it cause many hot kernel spinlocks from __kmalloc and kfree  respectively
> with original spinlock cpu cost 25% and  92715428576 cycles after
> lock/unlock 1000000 times
> with ali spinlock cpu cost 15% and  48475891244 cycles after
> lock/unlock 1000000 times.
> So we say in the real world workload the ali spinlock improve
> performance by 1.9x
> (92715428576 cycles/48475891244 cycles)
>
> Thanks
> Ling
>
> the
>
> 2016-01-12 21:50 GMT+08:00 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>:
>> On Sat, 9 Jan 2016 06:44:15 +0800
>> Ling Ma <ling.ma.program@gmail.com> wrote:
>>
>>> The attachment (alispinlock.tar.bz2) includes original spinlock and
>>> alispinlock ,
>>> we compare them on 70 cores based on kernel 4.3, the alispinlock can
>>> improve performance upto 3x.
>>>
>>> the link: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1035940.html
>>> indicates when we introduce the idea for real application(user space
>>> application  caused the bottle neck from  kernel spinlock )
>>> the spinlock performance is improved by 1.9x (perf top -d1 also tell
>>> us the spinlock cost time is reduced from 25% to 15%).
>>>
>>> Appreciate your comments
>>
>> So this has not been applied to actual real kernel locks (ie converted
>> some of the hot kernel locks to it) and then benchmarked with a real
>> world workload. This is just for the theoretical locking overhead ?
>>
>> Alan

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#1312333

On 01/19/2016 03:52 AM, Ling Ma wrote:
> Is it acceptable for performance improvement or more comments on this patch?
>
> Thanks
> Ling
>
>

Your alispinlock patchset should also include a use case where the lock 
is used by some code within the kernel with test that can show a 
performance improvement so that the reviewers can independently try it 
out and play around with it. The kernel community will not accept any 
patch without a use case in the kernel.

Your lock_test.tar file is not good enough as it is not a performance 
test of the patch that you sent out.

Cheers,
Longman

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