Re: [patch] mm: more likely reclaim MADV_SEQUENTIAL mappings II

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> mmotm:
>     normal  user: 1.775000s [0.053307] system: 9.620000s [0.135339] total: 98.875000s [0.613956]
>    madvise  user: 2.552500s [0.041307] system: 9.442500s [0.075980] total: 73.937500s [0.734170]
> mmotm+patch:
>     normal  user: 1.850000s [0.013540] system: 9.760000s [0.047081] total: 99.250000s [0.569386]
>    madvise  user: 2.547500s [0.014930] system: 8.865000s [0.055000] total: 71.897500s [0.144763]
> 
> Well, time-wise not sooo much of an improvement.  But given the
> massively decreased LRU-rotation [ http://hannes.saeurebad.de/madvseq/ ]

My first impression, this result mean the patch is not so useful.
But anyway, I mesured it again because I think Nick's opinion is very
reasonable and I don't know your mesurement condition so detail.



> I'm still looking forward to Kosaki-san's throughput measurements :)

I'm sorry for late responce.
but I'd like to you know this mesurement need spent long time in my time.


1. copybench (http://code.google.com/p/copybench/)

   my machine mem:   8GB
   target file size: 10GB (filesize > system mem)


                         mmotm-1022  + the patch
   ==============================================================
   rw_cp                 6:32        6:34
   rw_fadv_cp            6:34        6:35
   mm_sync_cp            6:15        6:16
   mm_sync_madv_cp       6:19        6:14
   mw_cp                 6:11        6:12
   mw_madv_cp            6:13        6:12


MADV_SEQUENTIAL decrease performance a bit on mmotm.
but the patch fix it.



2. MADV_SEQUENTIAL vs dbench

                         mmotm1022   + the patch
   ==============================================================
   mm_sync_madv_cp       6:29        6:19           (min:sec)
   dbench throughput     11.633      14.4045        (MB/s)
   dbench latency        65628       18565          (ms)


mmotm's copy decrease performance largely. but the patch decrease it a bit. 
dbench throuput improve about 25%, latency improve about 3.5 times.


So, I think the patch better than v1 and we should appreciate for Nick's
good suggestion.

Hanns, Actually I recomend to spent a bit more time for proper benchmark design and settings.


	Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>



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