trace: branch profiling should not print percent without data
Impact: cleanup on output of branch profiler
When a branch has not been taken, it does not make sense to show
a percentage incorrect or hit. This patch changes the behaviour
to print out a 'X' when the branch has not been executed yet.
For example:
correct incorrect % Function File Line
------- --------- - -------- ---- ----
2096 0 0 do_arch_prctl process_64.c 832
0 0 X do_arch_prctl process_64.c 804
2604 0 0 IS_ERR err.h 34
130228 5765 4 __switch_to process_64.c 673
0 0 X enable_TSC process_64.c 448
0 0 X disable_TSC process_64.c 431
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 21dedc8..142acb3 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -225,7 +225,7 @@
{
struct ftrace_branch_data *p = v;
const char *f;
- unsigned long percent;
+ long percent;
if (v == (void *)1) {
seq_printf(m, " correct incorrect %% "
@@ -247,9 +247,13 @@
percent = p->incorrect * 100;
percent /= p->correct + p->incorrect;
} else
- percent = p->incorrect ? 100 : 0;
+ percent = p->incorrect ? 100 : -1;
- seq_printf(m, "%8lu %8lu %3lu ", p->correct, p->incorrect, percent);
+ seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
+ if (percent < 0)
+ seq_printf(m, " X ");
+ else
+ seq_printf(m, "%3ld ", percent);
seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
return 0;
}