Re: [PATCH v4 4/7] Reclaim invalidated page ASAP

[Minchan Kim]

On Wed, Dec 8, 2010 at 10:01 PM, Ben Gamari <bgamari.foss@xxxxxxxxx> wrote:
>> Make sense to me. If Ben is busy, I will measure it and send the result.
>
> I've done measurements on the patched kernel. All that remains is to do
> measurements on the baseline unpached case. To summarize the results
> thusfar,
>
> Times:
> =======
>                       user    sys     %cpu    inputs           outputs
> Patched, drop          142     64      46      13557744         14052744
> Patched, nodrop        55      57      33      13557936         13556680
>
> vmstat:
> ========
>                        free_pages      inact_anon      act_anon        inact_file      act_file        dirtied      written  reclaim
> Patched, drop, pre      306043          37541           185463          276266          153955          3689674      3604959  1550641
> Patched, drop, post     13233           38462           175252          536346          178792          5527564      5371563  3169155
>
> Patched, nodrop, pre    475211          38602           175242          81979           178820          5527592      5371554  3169155
> Patched, nodrop, post   7697            38959           176986          547984          180855          7324836      7132158  3169155
>
> Altogether, it seems that something is horribly wrong, most likely with
> my test (or rsync patch). I'll do the baseline benchmarks today.
>
> Thoughts?


How do you test it?
I think patch's effect would be good in big memory pressure environment.

Quickly I did it on my desktop environment.(2G DRAM)
So it's not completed result. I will test more when out of office.

Used kernel : mmotm-12-02 + my patch series
Used rsync :
1. rsync_normal : v3.0.7 vanilla
2. rsync_patch : v3.0.7 + Ben's patch(fadvise)

Test scenario :
* kernel full compile
* git clone linux-kernel
* rsync local host directory to local host dst directory


1) rsync_normal : 89.08user 127.48system 33:22.24elapsed
2) rsync_patch : 88.42user 135.26system 31:30.56elapsed

1) rsync_normal vmstat :
pgfault : 45538203
pgmajfault : 4181

pgactivate 377416
pgdeactivate 34183
pginvalidate 0
pgreclaim 0

pgsteal_dma 0
pgsteal_normal 2144469
pgsteal_high 2884412
pgsteal_movable 0
pgscan_kswapd_dma 0
pgscan_kswapd_normal 2149739
pgscan_kswapd_high 2909140
pgscan_kswapd_movable 0
pgscan_direct_dma 0
pgscan_direct_normal 647
pgscan_direct_high 716
pgscan_direct_movable 0
pginodesteal 0
slabs_scanned 1737344
kswapd_steal 5028353
kswapd_inodesteal 438910
pageoutrun 81208
allocstall 9
pgrotated 1642

2) rsync_patch vmstat:

pgfault : 47570231
pgmajfault : 2669

pgactivate 391806
pgdeactivate 36861
pginvalidate 1685065
pgreclaim 1685065

pgrefill_dma 0
pgrefill_normal 32025
pgrefill_high 9619
pgrefill_movable 0
pgsteal_dma 0
pgsteal_normal 744904
pgsteal_high 1079709
pgsteal_movable 0
pgscan_kswapd_dma 0
pgscan_kswapd_normal 745017
pgscan_kswapd_high 1096660
pgscan_kswapd_movable 0
pgscan_direct_dma 0
pgscan_direct_normal 0
pgscan_direct_high 0
pgscan_direct_movable 0
pginodesteal 0
slabs_scanned 1896960
kswapd_steal 1824613
kswapd_inodesteal 703499
pageoutrun 26828
allocstall 0
pgrotated 1681570

In summary,
Unfortunately, the number of fault is increased (47570231 - 45538203)
but pgmajfault is reduced (4181 - 2669).

The number of scanning is much reduced. 2149739 -> 745017, 2909140 ->
1096660 and even no direct reclaim in patched rsync.

The number of steal is much reduced. 2144469 -> 744904, 2884412 ->
1079709, 5028353 -> 1824613.

The elapsed time is reduced 2 minutes.

I think result is good. Reduced the steal number could imply prevent
eviction of working set pages.

It has a good result with small effort(small scanning).

I will resend with more exact measurement after repeated test.

> Thanks,
>
> - Ben
>
>



-- 
Kind regards,
Minchan Kim
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