linux-kernel - Re: [PATCH v4 2/4] zram: implement deduplication in zram

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Date:   Wed, 26 Apr 2017 15:21:04 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Joonsoo Kim <js1304@...il.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Minchan Kim <minchan@...nel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        linux-kernel@...r.kernel.org, kernel-team@....com
Subject: Re: [PATCH v4 2/4] zram: implement deduplication in zram

On (04/26/17 15:04), Joonsoo Kim wrote:
> On Wed, Apr 26, 2017 at 01:02:43PM +0900, Sergey Senozhatsky wrote:
> > On (04/26/17 09:52), js1304@...il.com wrote:
> > [..]
> > > <no-dedup>
> > > Elapsed time: out/host: 88 s
> > > mm_stat: 8834420736 3658184579 3834208256 0 3834208256 32889 0 0 0
> > > 
> > > <dedup>
> > > Elapsed time: out/host: 100 s
> > > mm_stat: 8832929792 3657329322 2832015360 0 2832015360 32609 0 952568877 80880336
> > > 
> > > It shows performance degradation roughly 13% and save 24% memory. Maybe,
> > > it is due to overhead of calculating checksum and comparison.
> > 
> > I like the patch set, and it makes sense. the benefit is, obviously,
> > case-by-case. on my system I've managed to save just 60MB on a 2.7G
> > data set, which is far less than I was hoping to save :)
> > 
> > 
> > I usually do DIRECT IO fio performance test. JFYI, the results
> > were as follows:
> 
> Could you share your fio test setting? I will try to re-generate the
> result and analyze it.

sure.

I think I used this one: https://github.com/sergey-senozhatsky/zram-perf-test

// hm... may be slightly modified on my box.

I'll run more tests.



what I did:

#0
ZRAM_SIZE=2G ZRAM_COMP_ALG=lzo LOG_SUFFIX=NO-DEDUP FIO_LOOPS=2 ./zram-fio-test.sh

#1
add `echo 1 > /sys/block/zram0/use_dedup` to create_zram
ZRAM_SIZE=2G ZRAM_COMP_ALG=lzo LOG_SUFFIX=DEDUP FIO_LOOPS=2 ./zram-fio-test.sh


both in ./conf/fio-template-static-buffer fio config.

and then

#2
./fio-perf-o-meter.sh /tmp/test-fio-zram-NO-DEDUP /tmp/test-fio-zram-DEDUP > /tmp/RES

	-ss