Re: [PATCH] perf trace: Simplify '--summary' output

From: Ingo Molnar
Date: Tue Nov 12 2013 - 16:33:46 EST



* Pekka Enberg <penberg@xxxxxxxxxx> wrote:

> The output of 'perf trace --summary' tries to be too cute with
> formatting and makes it very hard to read. Simplify it in the spirit of
> "strace -c":
>
> [penberg@localhost libtrading]$ perf trace -a --duration 10000 --summary -- sleep 1
> ^C

Btw., just a very small feature suggestion - instead of forcing the
somewhat counter-intuitive '-- sleep X' pattern it might be helpful to
have a general option parser for 'delay' values, which would allow a wide
range of time units like:

--delay 10.5h
--delay 0.1s
--delay 0.1sec

etc. - with the default unit being 'seconds'.

That parser could then be applied to '--duration' filter as well, allowing
things like:

--duration 10sec

which IMHO are more obvious to read (and easier to remember!) than
'--duration 10000'.

> Summary of events:
>
> dbus-daemon (555), 10 events, 0.0%, 0.000 msec
>
> msec/call
> syscall calls min avg max stddev
> --------------- -------- -------- -------- -------- ------
> sendmsg 2 0.002 0.005 0.008 55.00
> recvmsg 2 0.002 0.003 0.005 44.00
> epoll_wait 1 0.000 0.000 0.000 0.00

In what units is stddev? Percentage? If yes then it might be useful to
output it as %. [and probably to restrict precision to a single digit,
standard deviations are rarely more accurate than 0.1%.]

> NetworkManager (667), 56 events, 0.0%, 0.000 msec
>
> msec/call
> syscall calls min avg max stddev
> --------------- -------- -------- -------- -------- ------
> poll 2 0.000 0.002 0.003 100.00
> sendmsg 10 0.004 0.007 0.016 15.41
> recvmsg 16 0.002 0.003 0.005 8.24
>
> zfs-fuse (669), 4 events, 0.0%, 0.000 msec
>
> msec/call
> syscall calls min avg max stddev
> --------------- -------- -------- -------- -------- ------
> futex 2 0.000 0.001 0.002 100.00

Nice looking output btw! :-)

Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>

Thanks,

Ingo
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