[CRIU] [PATCH] [RFC] perf: Here is an example how to trace syscalls

[Andrew Vagin]

On Mon, Oct 06, 2014 at 09:30:02AM -0400, Christopher Covington wrote:
> On 10/01/2014 04:03 AM, Andrew Vagin wrote:
> > On Tue, Sep 30, 2014 at 01:23:55PM -0400, Christopher Covington wrote:
> >> On 09/30/2014 08:05 AM, Andrey Vagin wrote:
> >>> perf doesn't affect performance so significant as strace and
> >>> it allows to trace parasite code.
> >>>
> >>> All processes are executed in a new perf_evets cgroup and
> >>> "perf record" collects events only for processes from this group.
> 
> >>
> >> Why do you need container based monitoring instead of just command-and-childen
> >> based with `perf record $CRIU_CPT`?
> > 
> > I want to trace parasite code, which is injected in dumped processes.
> 
> I think putting this in the commit message and/or comments would be helpful.

Yes, sure.

> How do you differentiate parasite versus pre-parasite/post-parasite original code?

Here is an example of output:
$ perf trace report -i /root/git/criu/test/dump/static/env00/1127/1/perf.dump
....
    29.946 ( 0.012 ms): criu/1146 write(fd: 1023, buf: 0x6b5940, count: 44                              ) = 44
    29.959 ( 0.012 ms): criu/1146 recvfrom(fd: 31, ubuf: 0x7fffa48f4e60, size: 12, flags: WAITALL       ) = 12
    29.973 ( 0.013 ms): criu/1146 write(fd: 1023, buf: 0x6b5940, count: 31                              ) = 31
    29.999 ( 0.088 ms): env00/1127 recvfrom(fd: 3, ubuf: 0x7fee6cdf0998, size: 12, flags: WAITALL        ) = 12
    30.013 ( 0.013 ms): env00/1127 write(fd: 4, buf: 0x7fee6cdf0878, count: 26                           ) = 26
    30.016 ( 0.002 ms): env00/1127 rt_sigaction(sig: HUP, oact: 0x7fee6cde6c60, sigsetsize: 8            ) = 0
    30.018 ( 0.001 ms): env00/1127 rt_sigaction(sig: INT, oact: 0x7fee6cde6c80, sigsetsize: 8            ) = 0
...

You can see how criu sends a command to parasite and then it handles the command.

And ont more example is how to get top 10 of syscalls:
[root at avagin-fc19-cr criu]# perf trace report -s -i /root/git/criu/test/dump/static/env00/1127/1/perf.dump | sort -n -k 2 -r | head -n 10
   syscall            calls      min       avg       max      stddev
                               (msec)    (msec)    (msec)        (%)
   write                764     0.012     0.017     0.110      2.62%
   close                165     0.001     0.001     0.009      3.39%
   openat               147     0.012     0.038     0.211      5.19%
   read                  93     0.001     0.012     0.077     13.78%
   ptrace                86     0.002     0.015     0.263     26.51%
   rt_sigaction          62     0.001     0.002     0.015     15.55%
   rt_sigaction          62     0.001     0.001     0.010     11.14%
   fstat                 45     0.001     0.002     0.027     26.85%
   prctl                 42     0.001     0.001     0.002      1.93%
   prctl                 42     0.001     0.001     0.001      1.75%

> 
> Thanks,
> Christopher
> 
> -- 
> Employee of Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by the Linux Foundation.