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

[Jerome Marchand]

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

Jerome

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