On Wed, Apr 26, 2017 at 01:02:43PM +0900, Sergey Senozhatsky wrote: > On (04/26/17 09:52), js1...@gmail.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. I guess that contention happens due to same data page. Could you check it? Thanks.