Re: [LKP] [lkp] [mm, oom] faad2185f4: vm-scalability.throughput -11.8% regression

Michal Hocko
2016-04-27T09:17:28Z

On Wed 27-04-16 16:44:31, Huang, Ying wrote:
> Michal Hocko <mhocko@kernel.org> writes:
>
> > On Wed 27-04-16 16:20:43, Huang, Ying wrote:
> >> Michal Hocko <mhocko@kernel.org> writes:
> >>
> >> > On Wed 27-04-16 11:15:56, kernel test robot wrote:
> >> >> FYI, we noticed vm-scalability.throughput -11.8% regression with the following commit:
> >> >
> >> > Could you be more specific what the test does please?
> >>
> >> The sub-testcase of vm-scalability is swap-w-rand. An RAM emulated pmem
> >> device is used as a swap device, and a test program will allocate/write
> >> anonymous memory randomly to exercise page allocation, reclaiming, and
> >> swapping in code path.
> >
> > Can I download the test with the setup to play with this?
>
> There are reproduce steps in the original report email.
>
> To reproduce:
>
> git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
> cd lkp-tests
> bin/lkp install job.yaml # job file is attached in this email
> bin/lkp run job.yaml
>
>
> The job.yaml and kconfig file are attached in the original report email.

Thanks for the instructions. My bad I have overlooked that in the
initial email. I have checked the configuration file and it seems rather
hardcoded for a particular HW. It expects a machine with 128G and
reserves 96G!4G which might lead to different amount of memory in the
end depending on the particular memory layout.

Before I go and try to recreate a similar setup, how stable are the
results from this test. Random access pattern sounds like rather
volatile to be consider for a throughput test. Or is there any other
side effect I am missing and something fails which didn't use to
previously.
--
Michal Hocko
SUSE Labs