Re: [PATCH 00/09] cifs: local caching support using FS-Cache

[Scott Lovenberg <scott.lovenberg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 7/22/2010 5:28 AM, Suresh Jayaraman wrote:
> Here are some results from my benchmarking:
>
> Environment
> ------------
>
> I'm using my T60p laptop as the CIFS server (running Samba) and one of
> my test machines as CIFS client, connected over an ethernet of reported
> speed 1000 Mb/s. The TCP bandwidth as seen by a pair of netcats between
> the client and the server is about 786.24 Mb/s.
>
> Client has a 2.8 GHz Pentium D CPU with 2GB RAM
> Server has a 2.33GHz Core2 CPU (T7600) with 2GB RAM
>
>
> Test
> -----
> The benchmark involves pulling a 200 MB file over CIFS to the client
> using cat to /dev/zero under `time'. The wall clock time reported was
> recorded.
>
> Note
> ----
>     - The client was rebooted after each test, but the server was not.
>     - The entire file was loaded into RAM on the server before each test
>       to eliminate disk I/O latencies on that end.
>     - A seperate partition of size 4GB has been dedicated for the cache.
>     - There were no other CIFS client that was accessing the Server when
>       the tests were performed.
>
>
> First, the test was run on the server twice and the second result was
> recorded (noted as Server below).
>
> Secondly, the client was rebooted and the test was run with cachefiled
> not running and was recorded (noted as None below).
>
> Next, the client was rebooted, the cache contents (if any) were erased
> with mkfs.ext3 and test was run again with cachefilesd running (noted as
> COLD)
>
> Next the client was rebooted, tests were run with cachefilesd running
> this time with a populated cache (noted as HOT).
>
> Finally, the test was run again without unmounting, stopping cachefiled
> or rebooting to ensure pagecache is valid (noted as PGCACHE).
>
> The benchmark was repeated twice:
>
> Cache (state)	Run #1		Run#2
> =============  =======		=======
> Server		0.107 s		0.090 s
> None		6.497 s		6.440 s
> COLD		6.707 s		6.635 s
> HOT		5.286 s		5.078 s
> PGCACHE		0.090 s		0.091 s
>
> As it can been seen, the performance while reading when data is cache
> hot (disk) is not great as the network link is a Gigabit ethernet (with
> server having working set in memory) which is mostly expected. (I could
> not get access to a slower network (say 100 Mb/s) where the real
> performance boost could be evident).
>
>
> Thanks,
>
>
>    

Suresh, thanks for taking the time to run these bench marks. :)