diff --git a/tools/profiling/microbenchmark/bm.py b/tools/profiling/microbenchmark/bm.py
index a9277379c7b..b4f0de841fd 100755
--- a/tools/profiling/microbenchmark/bm.py
+++ b/tools/profiling/microbenchmark/bm.py
@@ -90,7 +90,7 @@ for bm_name in sys.argv[1:]:
        'CONFIG=mutrace', '-j', '%d' % multiprocessing.cpu_count()])
   for line in subprocess.check_output(['bins/mutrace/%s' % bm_name,
                                        '--benchmark_list_tests']).splitlines():
-    subprocess.check_call(['sudo', 'perf', 'record', '-g', '-F', '99',
+    subprocess.check_call(['sudo', 'perf', 'record', '-g', '-c', '1000',
                            'bins/mutrace/%s' % bm_name,
                            '--benchmark_filter=^%s$' % line,
                            '--benchmark_min_time=20'])