Re: [PATCH 0/1] mm, shmem: map few pages around fault address if they are in page cache

[Ning Qu <quning@xxxxxxxxxx>]

let me double check.

Best wishes,

-- 
Ning Qu (曲宁) | Software Engineer | quning@xxxxxxxxxx | +1-408-418-6066

On Fri, Feb 28, 2014 at 2:34 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

On Fri, 28 Feb 2014 14:18:50 -0800 Ning Qu <quning@xxxxxxxxxx> 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
>