Re: [PATCH] Implement --delay on perf trace

[Arnaldo Carvalho de Melo]

Em Mon, Oct 10, 2016 at 07:43:27AM +0200, Alexis Berlemont escreveu:
> Hi,
> 
> In the perf wiki todo-list, there is an entry regarding initial-delay and
> perf trace; the following small patch tries to fulfill this point. It
> has been generated against the branch tip/perf/core.
> 
> It has only been implemented in the "trace__run" case.

Ok, moved the description to the cset comment and added the entry to
tools/perf/Documentation/perf-trace.txt, i.e. to its man page, just
copying from the exact same description in 'perf stat' and 'perf
record's ones.

What is next? :-)

- Arnaldo
 
> Ex.:
> 
> $ sudo strace -- ./perf trace --delay 5 sleep 1 2>&1
> ...
> fcntl(7, F_SETFL, O_RDONLY|O_NONBLOCK)  = 0
> ioctl(7, PERF_EVENT_IOC_ID, 0x7ffc8fd35718) = 0
> ioctl(11, PERF_EVENT_IOC_SET_OUTPUT, 0x7) = 0
> fcntl(11, F_SETFL, O_RDONLY|O_NONBLOCK) = 0
> ioctl(11, PERF_EVENT_IOC_ID, 0x7ffc8fd35718) = 0
> write(6, "\0", 1)                       = 1
> close(6)                                = 0
> nanosleep({0, 5000000}, NULL)           = 0  # DELAY OF 5 MS BEFORE ENABLING THE EVNTS
> ioctl(3, PERF_EVENT_IOC_ENABLE, 0)      = 0
> ioctl(4, PERF_EVENT_IOC_ENABLE, 0)      = 0
> ioctl(5, PERF_EVENT_IOC_ENABLE, 0)      = 0
> ioctl(7, PERF_EVENT_IOC_ENABLE, 0)      = 0
> ...
> 
> Alexis.
> 
> Alexis Berlemont (1):
>   perf: implement --delay on perf trace
> 
>  tools/perf/builtin-trace.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> -- 
> 2.10.0