Ignore EV_DOMAIN_CONDITION_WAIT

We don't know what systhread it came from, so we can't display it
sensibly anyway.

Also, don't crash trying to pop an empty stack; we might have missed an
event.

Author: talex5

lib/trace.ml

@@ -52,12 +52,13 @@ module Ring = struct
     t.events <- (ts, e :: stack) :: t.events
 
   let pop t ts =
-    let stack =
+    let tail =
       match t.events with
+      | (_, (_ :: x)) :: _ -> x
       | [] -> []
-      | (_, s) :: _ -> s
+      | _ :: _ -> print_endline "warning: unmatched pop!"; []
     in
-    t.events <- (ts, List.tl stack) :: t.events
+    t.events <- (ts, tail) :: t.events
 end
 
 type t = {

src/record.ml

@@ -41,21 +41,27 @@ let get_fiber t id =
     t.fibers <- Fibers.add id x t.fibers;
     x
 
+let phase_useful = function
+  | Runtime_events.EV_DOMAIN_CONDITION_WAIT -> false    (* We don't know what systhread it came from *)
+  | _ -> true
+
 let callbacks t =
   Runtime_events.Callbacks.create ()
     ~runtime_begin:(fun ring ts phase ->
-        Write.duration_begin t.fxt
-          ~thread:(ring_thread t ring)
-          ~name:(Runtime_events.runtime_phase_name phase)
-          ~category:"gc"
-          ~ts:(Runtime_events.Timestamp.to_int64 ts)
+        if phase_useful phase then
+          Write.duration_begin t.fxt
+            ~thread:(ring_thread t ring)
+            ~name:(Runtime_events.runtime_phase_name phase)
+            ~category:"gc"
+            ~ts:(Runtime_events.Timestamp.to_int64 ts)
       )
     ~runtime_end:(fun ring ts phase ->
-        Write.duration_end t.fxt
-          ~thread:(ring_thread t ring)
-          ~name:(Runtime_events.runtime_phase_name phase)
-          ~category:"gc"
-          ~ts:(Runtime_events.Timestamp.to_int64 ts)
+        if phase_useful phase then
+          Write.duration_end t.fxt
+            ~thread:(ring_thread t ring)
+            ~name:(Runtime_events.runtime_phase_name phase)
+            ~category:"gc"
+            ~ts:(Runtime_events.Timestamp.to_int64 ts)
       )
     ~lost_events:(fun ring n -> traceln "Warning: ring %d lost %d events" ring n)
   |> Eio_runtime_events.add_callbacks