Re: [PATCH v2] sched/completion: convert completions to use simple wait queues

From: Daniel Wagner
Date: Mon May 23 2016 - 10:10:19 EST


[Sorry for the late response. I was a few days on holiday]

On 05/16/2016 10:38 PM, Luiz Capitulino wrote:
> On Thu, 12 May 2016 16:08:34 +0200
> Daniel Wagner <wagi@xxxxxxxxx> wrote:
>
>> In short, I haven't figured out yet why the kernel builds get slightly slower.
>
> You're doing make -j 200, right? How many cores do you have? Couldn't it
> be that you're saturating your CPUs?

For the above numbers I used mmtest as test framework with 2x<NR CPUs>,
that is 128.

> You could try make -j<NR CPUs>, or some process creation benchmark. Although
> I don't know what's the best way to measure this.

Yeah, I consider the kernel benchmark not as a good workload to figure
out what's going on. It's more like to see something is hiding. The
micro benchmarks I used so far couldn't highlight the problem(s). I
guess more testing is needed.

cheers,
daniel