Re: [lkp] [futex] 65d8fc777f: +25.6% will-it-scale.per_process_ops

[Davidlohr Bueso]

On Mon, 29 Feb 2016, Ingo Molnar wrote:

> * kernel test robot <ying.huang@xxxxxxxxxxxxxxx> wrote:
>
> > FYI, we noticed the below changes on
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> > commit 65d8fc777f6dcfee12785c057a6b57f679641c90 ("futex: Remove requirement for
> > lock_page() in get_futex_key()")
>
> I have asked for this before, but let me try again: could you _PLEASE_ make these
> emails more readable?
>
> For example what are the 'below changes'? Changes in the profile output? Profiles
> always change from run to run, so that alone is not informative.
>
> Also, there are a lot of changes - which ones prompted the email to be generated?
>
> All in one, this email is hard to parse, because it just dumps a lot of
> information with very little explanatory structure for someone not versed in their
> format. Please try to create an easy to parse 'story' that leads the reader
> towards what you want these emails to tell - not just a raw dump of seemingly
> unconnected pieces of data ...
> â??
> Thanks,
>
> 	Ingo
>
> > =========================================================================================
> > compiler/cpufreq_governor/kconfig/rootfs/tbox_group/test/testcase:
> >   gcc-4.9/performance/x86_64-rhel/debian-x86_64-2015-02-07.cgz/lkp-sbx04/futex1/will-it-scale

If I'm reading this correctly, it is similar to what I measured wrt ~lockleless get_futex_key()
stuff using the perf runs, with similar performance improvement numbers (per process/thread ops).
The futex1 test will just pound on FUTEX_WAKE without anyone actually blocked on a futex, so it
mainly measures the key/hashing part of the operation.

Thanks,
Davidlohr