Optimize functions on a second thread.

test/cctest/test-mark-compact.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 508 matching lines @@
 
     line_start = position;
   }
   close(fd);
   return memory_use;
 }
 
 
 TEST(BootUpMemoryUse) {
   intptr_t initial_memory = MemoryInUse();
-  FLAG_crankshaft = false;  // Avoid flakiness.
+  // Avoid flakiness.
+  FLAG_crankshaft = false;
+  FLAG_parallel_recompilation = false;
+
   // Only Linux has the proc filesystem and only if it is mapped.  If it's not
   // there we just skip the test.
   if (initial_memory >= 0) {
     InitializeVM();
     intptr_t delta = MemoryInUse() - initial_memory;
     if (sizeof(initial_memory) == 8) {
       if (v8::internal::Snapshot::IsEnabled()) {
         CHECK_LE(delta, 3600 * 1024);  // 3396.
       } else {
         CHECK_LE(delta, 4000 * 1024);  // 3948.
       }
     } else {
       if (v8::internal::Snapshot::IsEnabled()) {
         CHECK_LE(delta, 2600 * 1024);  // 2484.
       } else {
         CHECK_LE(delta, 2950 * 1024);  // 2844
       }
     }
   }
 }
 
 #endif  // __linux__ and !USE_SIMULATOR