[PATCH] Implement --delay on perf trace

[Alexis Berlemont <alexis.berlemont@gmail.com>]

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.

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