perf record: Fall back to cpu-clock-ticks if no PMU
On architectures/CPUs without PMU support but with perfcounters
enabled 'perf record' currently fails because it cannot create a
cycle based hw-perfcounter.
Fall back to the cpu-clock-tick sw-perfcounter in this case, which
is hrtimer based and will always work (as long as perfcounters
are enabled).
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 6da30a1..1f8c97d 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -65,6 +65,7 @@
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 @@
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 @@
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 @@
"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()
};