diff --git a/include/aos/performance.h b/include/aos/performance.h
index b093fa3..70c9e16 100644
--- a/include/aos/performance.h
+++ b/include/aos/performance.h
@@ -9,19 +9,19 @@
 // #define PERFORMANCE_ENABLED
 
 struct measurement {
-    char *tag;
+    const char *tag;
     systime_t timestamp;
 };
 
 struct performance_context {
     size_t count;
-    char *name;
+    const char *name;
     struct measurement measurements[PERFORMANCE_MEASUREMENT_COUNT_MAX];
 };
 
-void perf_init(struct performance_context *c, char *name);
-void perf_add_measurement(struct performance_context *c, char *tag, systime_t timestamp);
-void perf_add_now(struct performance_context *c, char *tag);
+void perf_init(struct performance_context *c, const char *name);
+void perf_add_measurement(struct performance_context *c, const char *tag, systime_t timestamp);
+void perf_add_now(struct performance_context *c, const char *tag);
 void perf_print(struct performance_context *c);
 
 #endif // LIBBARRELFISH_PERFORMANCE_H
diff --git a/lib/aos/performance.c b/lib/aos/performance.c
index 9eb0e8c..77cbd1e 100644
--- a/lib/aos/performance.c
+++ b/lib/aos/performance.c
@@ -3,15 +3,18 @@
 #include <aos/systime.h>
 #include <string.h>
 
-void perf_init(struct performance_context *c, char *name) {
+void perf_init(struct performance_context *c, const char *name) {
     c->count = 0;
     c->name = name;
-    memset(c->measurements, 0, sizeof(c->measurements));
 }
 
-inline void perf_add_measurement(struct performance_context *c, char *tag, systime_t timestamp)
+inline void perf_add_measurement(struct performance_context *c, const char *tag, systime_t timestamp)
 {
     assert(c->count < PERFORMANCE_MEASUREMENT_COUNT_MAX);
+    
+    __asm volatile (
+        "dmb sy\n"
+    );
     c->measurements[c->count].tag = tag;
     c->measurements[c->count].timestamp = timestamp;
     c->count++;
@@ -20,7 +23,7 @@ inline void perf_add_measurement(struct performance_context *c, char *tag, systi
     );
 }
 
-inline void perf_add_now(struct performance_context *c, char *tag)
+inline void perf_add_now(struct performance_context *c, const char *tag)
 {
     systime_t now = systime_now();
     perf_add_measurement(c, tag, now);