Re: [PATCHv7 00/29] THP-enabled tmpfs/shmem using compound pages

[Shi, Yang]

On 4/19/2016 7:33 AM, Jerome Marchand wrote:
> On 04/19/2016 12:55 AM, Shi, Yang wrote:
> > 2. I ran my THP test (generated a program with 4MB text section) on both
> > x86-64 and ARM64 with yours and Hugh's patches (linux-next tree), I got
> > the program execution time reduced by ~12% on x86-64, it looks very
> > impressive.
> >
> > But, on ARM64, there is just ~3% change, and sometimes huge tmpfs may
> > show even worse data than non-hugepage.
> >
> > Both yours and Hugh's patches has the same behavior.
> >
> > Any idea?
>
> Just a shot in the dark, but what page size do you use? If you use 4k
> pages, then hugepage size should be the same as on x86 and a similar

I do use 4K pages for both x86-64 and ARM64 in my testing.

Thanks,
Yang

> behavior could be expected. Otherwise, hugepages would be too big to be
> taken advantage of by your test program.
>
> Jerome