perf tools: Make the breakpoint events sample period default to 1
There have one problem about hw_breakpoint perf event, as watched, the
events reported to userspace is not correctly, sometime one trigger
bp_event report several events, sometime bp_event cannot go through to
user.
The root cause is attr->freq is 1 passed to kernel defaultly in bp
events, this make kernel calculate event period not as expect, make
sample period to 1 will change attr->freq to 0, to fix this problem.
This patch is similar with commit f92128 about tracepoint events:
perf: Make the trace events sample period default to 1
Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/CACV3sbLF8taiCq_VYW-sgRJyupeMzg58C7ZXfMe3xZUiH_Mx6w@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a729945..74a5af4 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -490,6 +490,7 @@
attr.bp_len = HW_BREAKPOINT_LEN_4;
attr.type = PERF_TYPE_BREAKPOINT;
+ attr.sample_period = 1;
return add_event(list, idx, &attr, NULL);
}