Re: [lkp-robot] [mm, vmscan] 5e56dfbd83: fsmark.files_per_sec -11.1% regression

Michal Hocko
2017-01-26T09:13:27Z

On Wed 25-01-17 12:27:06, Ye Xiaolong wrote:
> On 01/24, Michal Hocko wrote:
> >On Mon 23-01-17 09:26:44, kernel test robot wrote:
> >>
> >> Greeting,
> >>
> >> FYI, we noticed a -11.1% regression of fsmark.files_per_sec due to commit:
> >>
> >>
> >> commit: 5e56dfbd837421b7fa3c6c06018c6701e2704917 ("mm, vmscan: consider eligible zones in get_scan_count")
> >> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> >
> >This is more than unexpected. This patch should be basically noop for
> >anything but CONFIG_HIGHMEM systems. And your config says this is 64b
> >kernel. Are those results reproducible? And could you try to compare
>
> Yes, the results are well reproducible, both the commit in question and its
> parent have ran for 4 times.
>
> >perf profiles before and after the patch.
>
> Here is the perf profiles,

I do not see any reclaim path in the profile... Could you take a
snapshot of /proc/vmstat and /proc/zoneinfo before and after the test
please?

--
Michal Hocko
SUSE Labs