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Date: Mon, 22 Aug 2016 09:40:52 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Sonny Rao <sonnyrao@chromium.org>, Jann Horn <jann@thejh.net>,
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Subject: Re: [PACTH v2 0/3] Implement /proc/<pid>/totmaps
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On Mon 22-08-16 09:07:45, Minchan Kim wrote:
[...]
> #!/bin/sh
> ./smap_test &
> pid=$!
> 
> for i in $(seq 25)
> do
>         awk '/^Rss/{rss+=$2} /^Pss/{pss+=$2} END {}' \
>          /proc/$pid/smaps
> done
> kill $pid
> 
> root@bbox:/home/barrios/test/smap# time ./s.sh 
> pid:21973
> 
> real    0m17.812s
> user    0m12.612s
> sys     0m5.187s

retested on the bare metal (x86_64 - 2CPUs)
        Command being timed: "sh s.sh"
        User time (seconds): 0.00
        System time (seconds): 18.08
        Percent of CPU this job got: 98%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 0:18.29

multiple runs are quite consistent in those numbers. I am running with
$ awk --version
GNU Awk 4.1.3, API: 1.1 (GNU MPFR 3.1.4, GNU MP 6.1.0)

> > like a problem we are not able to address. And I would even argue that
> > we want to address it in a generic way as much as possible.
> 
> Sure. What solution do you think as generic way?

either optimize seq_printf or replace it with something faster.

-- 
Michal Hocko
SUSE Labs