Re: [LKP] [mm] 3484b2de949: -46.2% aim7.jobs-per-min

Huang Ying
2015-02-28T02:42:54Z

On Sat, 2015-02-28 at 10:30 +0800, Huang Ying wrote:
> On Sat, 2015-02-28 at 01:46 +0000, Mel Gorman wrote:
> > On Fri, Feb 27, 2015 at 03:21:36PM +0800, Huang Ying wrote:
> > > FYI, we noticed the below changes on
> > >
> > > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > > commit 3484b2de9499df23c4604a513b36f96326ae81ad ("mm: rearrange zone fields into read-only, page alloc, statistics and page reclaim lines")
> > >
> > > The perf cpu-cycles for spinlock (zone->lock) increased a lot. I suspect there are some cache ping-pong or false sharing.
> > >
> >
> > Are you sure about this result? I ran similar tests here and found that
> > there was a major regression introduced near there but it was commit
> > 05b843012335 ("mm: memcontrol: use root_mem_cgroup res_counter") that
> > cause the problem and it was later reverted. On local tests on a 4-node
> > machine, commit 3484b2de9499df23c4604a513b36f96326ae81ad was within 1%
> > of the previous commit and well within the noise.
>
> I have double checked the result before sending out.
>
> Do you do the test with same kernel config and test case/parameters
> (aim7/page_test/load 6000)?

Or you can show your test case and parameters and I can try that too.

Best Regards,
Huang, Ying