Don't always compact when collecting.

src/flag-definitions.h

 // Copyright 2011 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 264 matching lines @@
 // liveobjectlist.cc
 DEFINE_string(lol_workdir, NULL, "path for lol temp files")
 DEFINE_bool(verify_lol, false, "perform debugging verification for lol")
 #endif
 
 // macro-assembler-ia32.cc
 DEFINE_bool(native_code_counters, false,
             "generate extra code for manipulating stats counters")
 
 // mark-compact.cc
-DEFINE_bool(always_compact, true, "Perform compaction on every full GC")
+DEFINE_bool(always_compact, false, "Perform compaction on every full GC")
 DEFINE_bool(lazy_sweeping, true,
             "Use lazy sweeping for old pointer and data spaces")
 DEFINE_bool(cleanup_caches_in_maps_at_gc, true,
             "Flush code caches in maps during mark compact cycle.")
 DEFINE_bool(never_compact, false,
             "Never perform compaction on full GC - testing only")
 DEFINE_bool(compact_code_space, false, "Compact code space")
 DEFINE_bool(cleanup_code_caches_at_gc, true,
             "Flush inline caches prior to mark compact collection and "
             "flush code caches in maps during mark compact cycle.")
@@ skipping 246 matching lines @@
 #undef FLAG
 
 #undef DEFINE_bool
 #undef DEFINE_int
 #undef DEFINE_string
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META