Re: [PATCH V2] Add the pagefault count into memcg stats

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Sun, 27 Mar 2011 20:26:00 -0700
Ying Han <yinghan@google.com> wrote:

> Two new stats in per-memcg memory.stat which tracks the number of
> page faults and number of major page faults.
> 
> "pgfault"
> "pgmajfault"
> 
> They are different from "pgpgin"/"pgpgout" stat which count number of
> pages charged/discharged to the cgroup and have no meaning of reading/
> writing page to disk.
> 
> It is valuable to track the two stats for both measuring application's
> performance as well as the efficiency of the kernel page reclaim path.
> Counting pagefaults per process is useful, but we also need the aggregated
> value since processes are monitored and controlled in cgroup basis in memcg.
> 
> Functional test: check the total number of pgfault/pgmajfault of all
> memcgs and compare with global vmstat value:
> 
> $ cat /proc/vmstat | grep fault
> pgfault 1070751
> pgmajfault 553
> 
> $ cat /dev/cgroup/memory.stat | grep fault
> pgfault 1071138
> pgmajfault 553
> total_pgfault 1071142
> total_pgmajfault 553
> 
> $ cat /dev/cgroup/A/memory.stat | grep fault
> pgfault 199
> pgmajfault 0
> total_pgfault 199
> total_pgmajfault 0
> 
> Performance test: run page fault test(pft) wit 16 thread on faulting in 15G
> anon pages in 16G container. There is no regression noticed on the "flt/cpu/s"
> 
> Sample output from pft:
> TAG pft:anon-sys-default:
>   Gb  Thr CLine   User     System     Wall    flt/cpu/s fault/wsec
>   15   16   1     0.69s   230.99s    14.62s   16972.539 268876.196
> 
> +-------------------------------------------------------------------------+
>     N           Min           Max        Median           Avg        Stddev
> x  10     16682.962     17344.027     16913.524     16928.812      166.5362
> +  10      16718.92     17023.453     16907.164     16902.399     88.468851
> No difference proven at 95.0% confidence
> 
> Signed-off-by: Ying Han <yinghan@google.com>

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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