[PATCH 0/5] trace-cmd profile enhancements

[Josef Bacik <jbacik@fb.com>]

I had to use trace-cmd profile to debug a regression with hhvm recently.  These
are the patches I needed to make trace-cmd profile useful to me.  There are a
few changes in here

1) Adding --merge to trace-cmd profile.  This merges events for like comms
together.  HHVM is a huge app that spawns worker threads to handle requests, I
needed all of this data in one place to see how the app as a whole was behaving,
--merge provides this.

2) Fixup the output formatting.  I also wanted to see which syscalls were taking
the longest but this was hard because we were just spitting out the syscall
number and it wasn't in any order, so now all the events are ordered based on
time taken and the syscall names are printed instead of the number.

3) Random trace-cmd hist fix, because it didn't work right with instances.

I've been using these in production for a couple of weeks now and they seem to
work well.  Thanks,

Josef