let me double check.

Best wishes,
-- 
Ning Qu (曲宁) | Software Engineer | quning@google.com | +1-408-418-6066


On Fri, Feb 28, 2014 at 2:34 PM, Andrew Morton <akpm@linux-foundation.org>wrote:

> On Fri, 28 Feb 2014 14:18:50 -0800 Ning Qu <quning@google.com> wrote:
>
> > This is a follow-up patch for "mm: map few pages around fault address if
> they are in page cache"
> >
> > We use the generic filemap_map_pages as ->map_pages in shmem/tmpfs.
> >
>
> Please cc Hugh on shmem/tmpfs things
>
> >
> > =========================================================================
> > Below is just some simple experiment numbers from this patch, let me
> know if
> > you would like more:
> >
> > Tested on Xeon machine with 64GiB of RAM, using the current default fault
> > order 4.
> >
> > Sequential access 8GiB file
> >                       Baseline        with-patch
> > 1 thread
> >     minor fault               205             101
>
> Confused.  Sequential access of an 8G file should generate 2,000,000
> minor faults, not 205.  And with FAULT_AROUND_ORDER=4, that should come
> down to 2,000,000/16 minor faults when using faultaround?
>
> >     time, seconds     7.94            7.82
> >
> > Random access 8GiB file
> >                       Baseline        with-patch
> > 1 thread
> >     minor fault               724             623
> >     time, seconds     9.75            9.84
> >
>
>