diff --git a/tools/perf/util/cache.h b/tools/perf/util/cache.h
index 7b176dd02e1ae94e6f5479b78ae4c2e84bb7836c..5cf9e1b5989de40cb677b1bd744d684cd3bfc871 100644
--- a/tools/perf/util/cache.h
+++ b/tools/perf/util/cache.h
@@ -22,6 +22,7 @@ typedef int (*config_fn_t)(const char *, const char *, void *);
 extern int perf_default_config(const char *, const char *, void *);
 extern int perf_config(config_fn_t fn, void *);
 extern int perf_config_int(const char *, const char *);
+extern u64 perf_config_u64(const char *, const char *);
 extern int perf_config_bool(const char *, const char *);
 extern int config_error_nonbool(const char *);
 extern const char *perf_config_dirname(const char *, const char *);
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 1e5e2e5af6b1d05b18b1f6b92b88c4e62e85f33c..9970b8b0190bbd91f161d95cdf0c6e38ffc72e41 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -286,6 +286,21 @@ static int parse_unit_factor(const char *end, unsigned long *val)
 	return 0;
 }
 
+static int perf_parse_llong(const char *value, long long *ret)
+{
+	if (value && *value) {
+		char *end;
+		long long val = strtoll(value, &end, 0);
+		unsigned long factor = 1;
+
+		if (!parse_unit_factor(end, &factor))
+			return 0;
+		*ret = val * factor;
+		return 1;
+	}
+	return 0;
+}
+
 static int perf_parse_long(const char *value, long *ret)
 {
 	if (value && *value) {
@@ -307,6 +322,15 @@ static void die_bad_config(const char *name)
 	die("bad config value for '%s'", name);
 }
 
+u64 perf_config_u64(const char *name, const char *value)
+{
+	long long ret = 0;
+
+	if (!perf_parse_llong(value, &ret))
+		die_bad_config(name);
+	return (u64) ret;
+}
+
 int perf_config_int(const char *name, const char *value)
 {
 	long ret = 0;