trace-cmd: Make a tighter record and less sleep
trace-cmd: Make a tighter record and less sleep

Make the reading of the trace_pipe_raw into a tight loop as
long as there is data read.

Also, if something was read last time, do not sleep before reading
again.

Signed-off-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

bigzz/trace-cmd,bigzz/trace-cmd