8336742: Shenandoah: Add more verbose logging/stats for mark terminat…

…ion attempts
neethu-prasad · Jul 24, 2024 · 7c3d4a8 · 7c3d4a8
1 parent c25c489
commit 7c3d4a8
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp b/src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp
@@ -205,7 +205,9 @@ void ShenandoahConcurrentMark::concurrent_mark() {
 
   ShenandoahSATBMarkQueueSet& qset = ShenandoahBarrierSet::satb_mark_queue_set();
   ShenandoahFlushSATBHandshakeClosure flush_satb(qset);
-  for (uint flushes = 0; flushes < ShenandoahMaxSATBBufferFlushes; flushes++) {
+  double handshake_total_time = 0;
+  uint flushes;
+  for (flushes = 0; flushes < ShenandoahMaxSATBBufferFlushes; flushes++) {
     TaskTerminator terminator(nworkers, task_queues());
     ShenandoahConcurrentMarkingTask<NON_GEN> task(this, &terminator);
     workers->run_task(&task);
@@ -216,14 +218,20 @@ void ShenandoahConcurrentMark::concurrent_mark() {
     }
 
     size_t before = qset.completed_buffers_num();
+    double handshake_start_time = os::elapsedTime();
     Handshake::execute(&flush_satb);
+    handshake_total_time += os::elapsedTime() - handshake_start_time;
     size_t after = qset.completed_buffers_num();
 
     if (before == after) {
       // No more retries needed, break out.
       break;
     }
   }
+  ShenandoahPhaseTimings* const timings = heap->phase_timings();
+  timings->record_phase_time(ShenandoahPhaseTimings::conc_mark_satb_flush_rendezvous, handshake_total_time);
+
+  log_info(gc, phases) ("Total SATB flush attempts : %d", (flushes + 1));
   assert(task_queues()->is_empty() || heap->cancelled_gc(), "Should be empty when not cancelled");
 }
 

diff --git a/src/hotspot/share/gc/shenandoah/shenandoahPhaseTimings.hpp b/src/hotspot/share/gc/shenandoah/shenandoahPhaseTimings.hpp
@@ -57,6 +57,7 @@ class outputStream;
   f(conc_mark_roots,                                "Concurrent Mark Roots ")          \
   SHENANDOAH_PAR_PHASE_DO(conc_mark_roots,          "  CMR: ", f)                      \
   f(conc_mark,                                      "Concurrent Marking")              \
+  f(conc_mark_satb_flush_rendezvous,                "  SATB Flush Rendezvous") \
                                                                                        \
   f(final_mark_gross,                               "Pause Final Mark (G)")            \
   f(final_mark,                                     "Pause Final Mark (N)")            \