diff --git a/include/dolphin/os.h b/include/dolphin/os.h
index e9d30f4b..d231c662 100644
--- a/include/dolphin/os.h
+++ b/include/dolphin/os.h
@@ -90,6 +90,23 @@ typedef struct OSCalendarTime {
 OSTime OSCalendarTimeToTicks(OSCalendarTime* td);
 void OSTicksToCalendarTime(OSTime ticks, OSCalendarTime* td);
 
+typedef struct OSStopwatch {
+	char* name;
+	OSTime total;
+	u32 hits;
+	OSTime min;
+	OSTime max;
+	OSTime last;
+	BOOL running;
+} OSStopwatch;
+
+void OSInitStopwatch(OSStopwatch* sw, char* name);
+void OSStartStopwatch(OSStopwatch* sw);
+void OSStopStopwatch(OSStopwatch* sw);
+OSTime OSCheckStopwatch(OSStopwatch* sw);
+void OSResetStopwatch(OSStopwatch* sw);
+void OSDumpStopwatch(OSStopwatch* sw);
+
 #define OS_CONSOLE_MASK 0xf0000000
 #define OS_CONSOLE_RETAIL 0x00000000
 #define OS_CONSOLE_DEVELOPMENT 0x10000000
diff --git a/src/game/perf.c b/src/game/perf.c
index 39918db8..09c40370 100644
--- a/src/game/perf.c
+++ b/src/game/perf.c
@@ -8,21 +8,14 @@ typedef struct {
     /* 0x04 */ char unk04[4];
     /* 0x08 */ s64 unk08;
     /* 0x10 */ s64 unk10;
-    /* 0x18 */ s32 unk18;
-    /* 0x1C */ char unk1C[0x34];
+    /* 0x18 */ OSStopwatch unk18;
     /* 0x50 */ s16 unk50;
     /* 0x52 */ char unk52[6];
 } UnknownPerfStruct; // Size 0x58
 
 static void DSCallbackFunc(u16 arg0);
 
-void OSInitStopwatch(void*, char*);
-void OSStartStopwatch(void*);
-u64 OSCheckStopwatch(void*);
-void OSResetStopwatch(void*);
-void OSStopStopwatch(void*);
-
-static u8 Ssw[56];
+static OSStopwatch Ssw;
 static UnknownPerfStruct perf[10];
 
 static u32 met0;