Re: [PATCH] sched: wakeup buddy

[Michael Wang <wangyun@linux.vnet.ibm.com>]

On 03/12/2013 04:48 PM, Ingo Molnar wrote:
[snip]
>>>
>>> Instrumentation/stats/profiling will also double check the correctness of 
>>> this data: if developers/users start relying on the work metric as a 
>>> substitute benchmark number, then app writers will have an additional 
>>> incentive to make them correct.
>>
>> I see, I could not figure out how to wisely using the info currently, 
>> but I have the feeling that it will make scheduler very different ;-)
>>
>> May be we could implement the API and get those info ready firstly 
>> (along with the new sched-pipe which provide work tick info), then think 
>> about the way to use them in scheduler, is there any patches on the way?
> 
> Absolutely.
> 
> Beyond the new prctl no new API is needed: a perf soft event could be 
> added, and/or a tracepoint. Then perf stat and perf record could be used 
> with it. 'perf bench' could be extended to generate the work tick in its 
> 'perf bench sched ...' workloads - and for 'perf bench mem numa' as well.

Nice :)

> 
> vsyscall-accelerating it could be a separate, more complex step: it needs 
> a per thread writable vsyscall data area to make the overhead to 
> applications near zero. Performance critical apps won't call an extra 
> syscall.

If it's really bring benefit, I think they will consider about it,
whatever, that's the developer/users decision, what we need to do is
just make the stuff attractively.

Regards,
Michael Wang

> 
> Thanks,
> 
> 	Ingo
>