diff --git a/chroprof/api.nim b/chroprof/api.nim
index f72cd19..fa4db62 100644
--- a/chroprof/api.nim
+++ b/chroprof/api.nim
@@ -11,16 +11,18 @@ proc getMetrics*(): MetricsTotals =
   ## current thread.
   result = profilerInstance.metrics
 
-proc enableProfiling*(callback: EventCallback = nil) =
+template enableProfiling*(callback: EventCallback) =
   ## Enables profiling for the the event loop running in the current thread.
   ## The client may optionally supply a callback to be notified of `Future`
   ## events.
   attachMonitoring(
-    if (isNil(callback)):
-      proc(e: Event) {.nimcall.} =
-        profilerInstance.processEvent(e)
-    else:
-      proc(e: Event) {.nimcall.} =
+      proc(e: Event) {.nimcall, gcsafe, raises: [].} =
         profilerInstance.processEvent(e)
         callback(e)
   )
+
+template enableProfiling*() =
+  attachMonitoring(
+    proc(e: Event) {.nimcall, gcsafe, raises: [].} =
+      profilerInstance.processEvent(e)
+  )
diff --git a/tests/testprofiler.nim b/tests/testprofiler.nim
index 90b1406..84b881e 100644
--- a/tests/testprofiler.nim
+++ b/tests/testprofiler.nim
@@ -282,23 +282,55 @@ suite "profiler metrics":
       await barrier
       advanceTime(10.milliseconds)
 
-    proc parent(): Future[Future[void]] {.async.} =
+    proc parent(): Future[seq[Future[void]]] {.async.} =
       advanceTime(10.milliseconds)
-      return child()
+      return @[child(), child()]
 
     let childFut = waitFor parent()
     barrier.complete()
-    waitFor childFut
+    waitFor allFutures(childFut)
 
     var metrics = recordedMetrics()
     let parentMetrics = metrics.forProc("parent")
     let childMetrics = metrics.forProc("child")
 
     check parentMetrics.execTime == 10.milliseconds
-    check parentMetrics.childrenExecTime == 10.milliseconds
+    check parentMetrics.childrenExecTime == 20.milliseconds
     check parentMetrics.wallClockTime == 10.milliseconds
 
-    echo "EXE TIME ", $childMetrics.execTime
+    check childMetrics.execTime == 20.milliseconds
+    check childMetrics.wallClockTime == 30.milliseconds
+    check childMetrics.childrenExecTime == ZeroDuration
+
+  test "should aggregate child execution times across nested children":
+    proc child() {.async.} =
+      advanceTime(10.milliseconds)
+
+    proc parent() {.async.} =
+      advanceTime(10.milliseconds)
+      await child()
+      advanceTime(10.milliseconds)
+
+    proc grandparent() {.async.} =
+      advanceTime(10.milliseconds)
+      await parent()
+      advanceTime(10.milliseconds)
+
+    waitFor grandparent()
+
+    var metrics = recordedMetrics()
+    let grandparentMetrics = metrics.forProc("grandparent")
+    let parentMetrics = metrics.forProc("parent")
+    let childMetrics = metrics.forProc("child")
+
+    check grandparentMetrics.execTime == 20.milliseconds
+    check grandparentMetrics.childrenExecTime == 30.milliseconds
+    check grandparentMetrics.wallClockTime == 50.milliseconds
+
+    check parentMetrics.execTime == 20.milliseconds
+    check parentMetrics.childrenExecTime == 10.milliseconds
+    check parentMetrics.wallClockTime == 30.milliseconds
+
     check childMetrics.execTime == 10.milliseconds
     check childMetrics.wallClockTime == 10.milliseconds
     check childMetrics.childrenExecTime == ZeroDuration