Trigger a profile before terminating worker upon timeout

src/ReTestItems.jl

@@ -554,7 +554,8 @@ function manage_worker(
             # Handle the exception
             if e isa TimeoutException
                 @debugv 1 "Test item $(repr(testitem.name)) timed out. Terminating worker $worker"
-                terminate!(worker)
+                trigger_profile(worker, :timeout)
+                terminate!(worker, :timeout)
                 wait(worker)
                 @error "$worker timed out running test item $(repr(testitem.name)) after $timeout seconds. \
                     Recording test error."

src/workers.jl

@@ -3,6 +3,7 @@ module Workers
 using Sockets, Serialization
 
 export Worker, remote_eval, remote_fetch, terminate!, WorkerTerminatedException
+export trigger_profile
 
 function try_with_timeout(f, timeout)
     cond = Threads.Condition()
@@ -105,6 +106,23 @@ function watch_and_terminate!(w::Worker, ev::Threads.Event)
     true
 end
 
+# Send signal to the given `Worker` process to trigger a profile.
+# Users can customise this profiling in the usual way, e.g. via
+# `JULIA_PROFILE_PEEK_HEAP_SNAPSHOT`, `Profile.set_peek_duration`, `Profile.peek_report[]`
+# See https://docs.julialang.org/en/v1/stdlib/Profile/#Triggered-During-Execution
+function trigger_profile(w::Worker, from::Symbol=:manual)
+    if !Sys.iswindows()
+        @debug "sending profile request to worker $(w.pid) from $from"
+        if Sys.islinux()
+            kill(w.process, 10)  # SIGUSR1
+        elseif Sys.isbsd()
+            kill(w.process, 29)  # SIGINFO
+        end
+    end
+    sleep(120) # Leave time for it to print the profile.
+    return nothing
+end
+
 # gracefully terminate a worker by sending a shutdown message
 # and waiting for the other tasks to perform worker shutdown
 function Base.close(w::Worker)