Re: [PATCHv2 0/9] split page table lock for PMD tables

[Kirill A. Shutemov]

Kirill A. Shutemov wrote:
> Alex Thorlton wrote:
> > > THP off:
> > > --------
> ...
> > >       36.540185552 seconds time elapsed                                          ( +- 18.36% )
> > 
> > I'm assuming this was THP off, no patchset, correct?
> 
> Yes. But THP off patched is *very* close to this, so I didn't post it separately.
> 
> > Here are my results from this test on 3.12-rc1:
> ...
> >     1138.759708820 seconds time elapsed                                          ( +-  0.47% )
> > 
> > And the same test on 3.12-rc1 with your patchset:
> > 
> >  Performance counter stats for './runt -t -c 512 -b 512m' (5 runs):
> ...
> >     1115.214191126 seconds time elapsed                                          ( +-  0.18% )
> > 
> > Looks like we're getting a mild performance increase here, but we still
> > have a problem.
> 
> Let me guess: you have HUGETLBFS enabled in your config, right? ;)
> 
> HUGETLBFS hasn't converted to new locking and we disable split pmd lock if
> HUGETLBFS is enabled.
> 
> I'm going to convert HUGETLBFS too, but it might take some time.

Okay, here is a bit reworked patch from Naoya Horiguchi.
It might need more cleanup.

Please, test and review.