1 files changed, 32 insertions, 26 deletions

diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c
index d8a26fd..246ab7d 100644
--- a/libgo/runtime/proc.c
+++ b/libgo/runtime/proc.c
@@ -2686,11 +2686,8 @@ runtime_mcount(void)
 }
 
 static struct {
-	Lock;
-	void (*fn)(uintptr*, int32);
+	uint32 lock;
 	int32 hz;
-	uintptr pcbuf[TracebackMaxFrames];
-	Location locbuf[TracebackMaxFrames];
 } prof;
 
 static void System(void) {}
@@ -2703,8 +2700,11 @@ runtime_sigprof()
 	M *mp = g->m;
 	int32 n, i;
 	bool traceback;
+	uintptr pcbuf[TracebackMaxFrames];
+	Location locbuf[TracebackMaxFrames];
+	Slice stk;
 
-	if(prof.fn == nil || prof.hz == 0)
+	if(prof.hz == 0)
 		return;
 
 	if(mp == nil)
@@ -2718,12 +2718,6 @@ runtime_sigprof()
 	if(mp->mcache == nil)
 		traceback = false;
 
-	runtime_lock(&prof);
-	if(prof.fn == nil) {
-		runtime_unlock(&prof);
-		mp->mallocing--;
-		return;
-	}
 	n = 0;
 
 	if(runtime_atomicload(&runtime_in_callers) > 0) {
@@ -2735,34 +2729,44 @@ runtime_sigprof()
 	}
 
 	if(traceback) {
-		n = runtime_callers(0, prof.locbuf, nelem(prof.locbuf), false);
+		n = runtime_callers(0, locbuf, nelem(locbuf), false);
 		for(i = 0; i < n; i++)
-			prof.pcbuf[i] = prof.locbuf[i].pc;
+			pcbuf[i] = locbuf[i].pc;
 	}
 	if(!traceback || n <= 0) {
 		n = 2;
-		prof.pcbuf[0] = (uintptr)runtime_getcallerpc(&n);
+		pcbuf[0] = (uintptr)runtime_getcallerpc(&n);
 		if(mp->gcing || mp->helpgc)
-			prof.pcbuf[1] = (uintptr)GC;
+			pcbuf[1] = (uintptr)GC;
 		else
-			prof.pcbuf[1] = (uintptr)System;
+			pcbuf[1] = (uintptr)System;
+	}
+
+	if (prof.hz != 0) {
+		stk.__values = &pcbuf[0];
+		stk.__count = n;
+		stk.__capacity = n;
+
+		// Simple cas-lock to coordinate with setcpuprofilerate.
+		while (!runtime_cas(&prof.lock, 0, 1)) {
+			runtime_osyield();
+		}
+		if (prof.hz != 0) {
+			runtime_cpuprofAdd(stk);
+		}
+		runtime_atomicstore(&prof.lock, 0);
 	}
-	prof.fn(prof.pcbuf, n);
-	runtime_unlock(&prof);
+
 	mp->mallocing--;
 }
 
 // Arrange to call fn with a traceback hz times a second.
 void
-runtime_setcpuprofilerate(void (*fn)(uintptr*, int32), int32 hz)
+runtime_setcpuprofilerate_m(int32 hz)
 {
 	// Force sane arguments.
 	if(hz < 0)
 		hz = 0;
-	if(hz == 0)
-		fn = nil;
-	if(fn == nil)
-		hz = 0;
 
 	// Disable preemption, otherwise we can be rescheduled to another thread
 	// that has profiling enabled.
@@ -2773,10 +2777,12 @@ runtime_setcpuprofilerate(void (*fn)(uintptr*, int32), int32 hz)
 	// it would deadlock.
 	runtime_resetcpuprofiler(0);
 
-	runtime_lock(&prof);
-	prof.fn = fn;
+	while (!runtime_cas(&prof.lock, 0, 1)) {
+		runtime_osyield();
+	}
 	prof.hz = hz;
-	runtime_unlock(&prof);
+	runtime_atomicstore(&prof.lock, 0);
+
 	runtime_lock(&runtime_sched);
 	runtime_sched.profilehz = hz;
 	runtime_unlock(&runtime_sched);