Re: [PATCH V5 0/8] Add memcg dirty/writeback page accounting

On Thu 01-08-13 19:43:22, Sha Zhengju wrote:
[...]

Some perforcemance numbers got by Mel's pft test (On a 4g memory and 4-core
i5 CPU machine):

I am little bit confused what is this testcase actually testing... AFAIU
it produces a lot of page faults but they are all anonymous and very
short lived. So neither dirty nor writeback accounting is done.

I would have expected a testcase which generates a lot of IO.

Also as a general note. It would be better to mention the number of runs
and standard deviation so that we have an idea about variability of the
load.

vanilla  : memcg enabled, patch not applied
patched  : all patches are patched

* Duration numbers:
             vanilla     patched
User          385.38      379.47
System         65.12       66.46
Elapsed       457.46      452.21

* Summary numbers:
vanilla:
Clients User        System      Elapsed     Faults/cpu  Faults/sec  
1       0.03        0.18        0.21        931682.645  910993.850  
2       0.03        0.22        0.13        760431.152  1472985.863 
3       0.03        0.29        0.12        600495.043  1620311.084 
4       0.04        0.37        0.12        475380.531  1688013.267

patched:
Clients User        System      Elapsed     Faults/cpu  Faults/sec  
1       0.02        0.19        0.22        915362.875  898763.732  
2       0.03        0.23        0.13        757518.387  1464893.996 
3       0.03        0.30        0.12        592113.126  1611873.469 
4       0.04        0.38        0.12        472203.393  1680013.271

We can see the performance gap is minor.

[...]
-- 
Michal Hocko
SUSE Labs

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