perf: Make the trace events sample period default to 1
Trace events are mostly used for tracing and then require not to
be lost when possible. As opposite to hardware events that really
require to trigger after a given sample period, trace events mostly
need to trigger everytime.
It is a frustrating experience to trace with perf and realize we
lost a lot of events because we forgot the "-c 1" option.
Then default sample_period to 1 for trace events but let the user
override it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de>