Introduce --job-based-sweeping flag and use individual jobs for sweeping if set

src/isolate.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1653 matching lines @@
     }
 
     for (int i = 0; i < num_sweeper_threads_; i++) {
       sweeper_thread_[i]->Stop();
       delete sweeper_thread_[i];
       sweeper_thread_[i] = NULL;
     }
     delete[] sweeper_thread_;
     sweeper_thread_ = NULL;
 
+    if (FLAG_job_based_sweeping &&
+        heap_.mark_compact_collector()->IsConcurrentSweepingInProgress()) {
+      heap_.mark_compact_collector()->WaitUntilSweepingCompleted();
+    }
 
     if (FLAG_hydrogen_stats) GetHStatistics()->Print();
 
     if (FLAG_print_deopt_stress) {
       PrintF(stdout, "=== Stress deopt counter: %u\n", stress_deopt_count_);
     }
 
     // We must stop the logger before we tear down other components.
     Sampler* sampler = logger_->sampler();
     if (sampler && sampler->IsActive()) sampler->Stop();
@@ skipping 319 matching lines @@
   if (create_heap_objects) heap_.CreateStubsRequiringBuiltins();
 
   // Set default value if not yet set.
   // TODO(yangguo): move this to ResourceConstraints::ConfigureDefaults
   // once ResourceConstraints becomes an argument to the Isolate constructor.
   if (max_available_threads_ < 1) {
     // Choose the default between 1 and 4.
     max_available_threads_ = Max(Min(CPU::NumberOfProcessorsOnline(), 4), 1);
   }
 
-  num_sweeper_threads_ = SweeperThread::NumberOfThreads(max_available_threads_);
+  if (!FLAG_job_based_sweeping) {
+    num_sweeper_threads_ =
+        SweeperThread::NumberOfThreads(max_available_threads_);
+  }
 
   if (FLAG_trace_hydrogen || FLAG_trace_hydrogen_stubs) {
     PrintF("Concurrent recompilation has been disabled for tracing.\n");
   } else if (OptimizingCompilerThread::Enabled(max_available_threads_)) {
     optimizing_compiler_thread_ = new OptimizingCompilerThread(this);
     optimizing_compiler_thread_->Start();
   }
 
   if (num_sweeper_threads_ > 0) {
     sweeper_thread_ = new SweeperThread*[num_sweeper_threads_];
@@ skipping 284 matching lines @@
 
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 } }  // namespace v8::internal