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-rw-r--r--tools/perf/builtin-top.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 6da30a140e86..1f8c97d5c32e 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -65,6 +65,7 @@ static int group = 0;
static unsigned int page_size;
static unsigned int mmap_pages = 16;
static int freq = 0;
+static int verbose = 0;
static char *sym_filter;
static unsigned long filter_start;
@@ -550,11 +551,12 @@ try_again:
if (fd[i][counter] < 0) {
int err = errno;
- error("sys_perf_counter_open() syscall returned with %d (%s)\n",
- fd[i][counter], strerror(err));
+ if (verbose)
+ error("sys_perf_counter_open() syscall returned with %d (%s)\n",
+ fd[i][counter], strerror(err));
if (err == EPERM)
- die(" No permission - are you root?\n");
+ die("No permission - are you root?\n");
/*
* If it's cycles then fall back to hrtimer
* based cpu-clock-tick sw counter, which
@@ -563,7 +565,9 @@ try_again:
if (attr->type == PERF_TYPE_HARDWARE
&& attr->config == PERF_COUNT_CPU_CYCLES) {
- warning(" ... trying to fall back to cpu-clock-ticks\n");
+ if (verbose)
+ warning(" ... trying to fall back to cpu-clock-ticks\n");
+
attr->type = PERF_TYPE_SOFTWARE;
attr->config = PERF_COUNT_CPU_CLOCK;
goto try_again;
@@ -673,6 +677,8 @@ static const struct option options[] = {
"profile at this frequency"),
OPT_INTEGER('E', "entries", &print_entries,
"display this many functions"),
+ OPT_BOOLEAN('v', "verbose", &verbose,
+ "be more verbose (show counter open errors, etc)"),
OPT_END()
};