8214259: Implementation: JEP 189: Shenandoah: A Low-Pause-Time Garbage Collector (Experimental)

Co-authored-by: Christine Flood <chf@redhat.com>
Co-authored-by: Aleksey Shipilev <shade@redhat.com>
Co-authored-by: Roland Westrelin <rwestrel@redhat.com>
Co-authored-by: Zhenygu Gu <zgu@redhat.com>
Co-authored-by: Andrew Haley <aph@redhat.com>
Co-authored-by: Andrew Dinn <adinn@redhat.com>
Co-authored-by: Mario Torre <mtorre@redhat.com>
Reviewed-by: kvn, roland, shade, coleenp, lmesnik, pliden, jgeorge, ihse, erikj

src/hotspot/share/gc/shenandoah/shenandoahTaskqueue.cpp

@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2016, 2018, Red Hat, Inc. All rights reserved.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+
+#include "gc/shenandoah/shenandoahHeap.hpp"
+#include "gc/shenandoah/shenandoahTaskqueue.hpp"
+#include "logging/log.hpp"
+#include "logging/logStream.hpp"
+
+void ShenandoahObjToScanQueueSet::clear() {
+  uint size = GenericTaskQueueSet<ShenandoahObjToScanQueue, mtGC>::size();
+  for (uint index = 0; index < size; index ++) {
+    ShenandoahObjToScanQueue* q = queue(index);
+    assert(q != NULL, "Sanity");
+    q->clear();
+  }
+}
+
+bool ShenandoahObjToScanQueueSet::is_empty() {
+  uint size = GenericTaskQueueSet<ShenandoahObjToScanQueue, mtGC>::size();
+  for (uint index = 0; index < size; index ++) {
+    ShenandoahObjToScanQueue* q = queue(index);
+    assert(q != NULL, "Sanity");
+    if (!q->is_empty()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+class ShenandoahOWSTTerminator: public OWSTTaskTerminator {
+public:
+  ShenandoahOWSTTerminator(uint n_threads, TaskQueueSetSuper* queue_set) :
+    OWSTTaskTerminator(n_threads, queue_set){ }
+
+protected:
+  bool exit_termination(size_t tasks, TerminatorTerminator* terminator);
+};
+
+bool ShenandoahOWSTTerminator::exit_termination(size_t tasks, TerminatorTerminator* terminator) {
+  ShenandoahTerminatorTerminator* t = (ShenandoahTerminatorTerminator*)terminator;
+  bool force = (t != NULL) && t->should_force_termination();
+  if (force) {
+    // Force termination : continue termination, even there are remaining tasks.
+    return false;
+  } else {
+    return OWSTTaskTerminator::exit_termination(tasks, terminator);
+  }
+}
+
+ShenandoahTaskTerminator::ShenandoahTaskTerminator(uint n_threads, TaskQueueSetSuper* queue_set) :
+  _terminator(new ShenandoahOWSTTerminator(n_threads, queue_set)) { }
+
+ShenandoahTaskTerminator::~ShenandoahTaskTerminator() {
+  assert(_terminator != NULL, "Invariant");
+  delete _terminator;
+}
+
+#if TASKQUEUE_STATS
+void ShenandoahObjToScanQueueSet::print_taskqueue_stats_hdr(outputStream* const st) {
+  st->print_raw_cr("GC Task Stats");
+  st->print_raw("thr "); TaskQueueStats::print_header(1, st); st->cr();
+  st->print_raw("--- "); TaskQueueStats::print_header(2, st); st->cr();
+}
+
+void ShenandoahObjToScanQueueSet::print_taskqueue_stats() const {
+  if (!log_develop_is_enabled(Trace, gc, task, stats)) {
+    return;
+  }
+  Log(gc, task, stats) log;
+  ResourceMark rm;
+  LogStream ls(log.trace());
+  outputStream* st = &ls;
+  print_taskqueue_stats_hdr(st);
+
+  ShenandoahObjToScanQueueSet* queues = const_cast<ShenandoahObjToScanQueueSet*>(this);
+  TaskQueueStats totals;
+  const uint n = size();
+  for (uint i = 0; i < n; ++i) {
+    st->print(UINT32_FORMAT_W(3), i);
+    queues->queue(i)->stats.print(st);
+    st->cr();
+    totals += queues->queue(i)->stats;
+  }
+  st->print("tot "); totals.print(st); st->cr();
+  DEBUG_ONLY(totals.verify());
+
+}
+
+void ShenandoahObjToScanQueueSet::reset_taskqueue_stats() {
+  const uint n = size();
+  for (uint i = 0; i < n; ++i) {
+    queue(i)->stats.reset();
+  }
+}
+#endif // TASKQUEUE_STATS