Add use of Psyco to GYP on Windows. On my z600 with 12 GB of RAM,

build/gyp_chromium

 #!/usr/bin/python
 
-# Copyright (c) 2009 The Chromium Authors. All rights reserved.
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script is wrapper for Chromium that adds some support for how GYP
 # is invoked by Chromium beyond what can be done in the gclient hooks.
 
 import glob
 import os
 import shlex
 import subprocess
 import sys
 
 script_dir = os.path.dirname(__file__)
 chrome_src = os.path.normpath(os.path.join(script_dir, os.pardir))
 
 sys.path.insert(0, os.path.join(chrome_src, 'tools', 'gyp', 'pylib'))
 import gyp
 
+# On Windows, Psyco shortens warm runs of build/gyp_chromium by about
+# 20 seconds on a z600 machine with 12 GB of RAM, from 90 down to 70
+# seconds.  Conversely, memory usage of build/gyp_chromium with Psyco
+# maxes out at about 158 MB vs. 132 MB without it.
+#
+# Psyco uses native libraries, so we need to load a different
+# installation depending on which OS we are running under. It has not
+# been tested whether using Psyco on our Mac and Linux builds is worth
+# it (the GYP running time is a lot shorter, so the JIT startup cost
+# may not be worth it).
+if sys.platform == 'win32':
+  try:
+    sys.path.insert(0, os.path.join(chrome_src, 'third_party', 'psyco_win32'))
+    import psyco
+  except:
+    psyco = None
+else:
+  psyco = None
+
 def apply_gyp_environment(file_path=None):
   """
   Reads in a *.gyp_env file and applies the valid keys to os.environ.
   """
   if not file_path or not os.path.exists(file_path):
     return
   file_contents = open(file_path).read()
   try:
     file_data = eval(file_contents, {'__builtins__': None}, None)
   except SyntaxError, e:
@@ skipping 40 matching lines @@
   # Optionally add supplemental .gypi files if present.
   supplements = glob.glob(os.path.join(chrome_src, '*', 'supplement.gypi'))
   for supplement in supplements:
     AddInclude(supplement)
 
   return result
 
 if __name__ == '__main__':
   args = sys.argv[1:]
 
+  # Use the Psyco JIT if available.
+  if psyco:
+    psyco.profile()
+    print "Enabled Psyco JIT."
+
   # Fall back on hermetic python if we happen to get run under cygwin.
   # TODO(bradnelson): take this out once this issue is fixed:
   #    http://code.google.com/p/gyp/issues/detail?id=177
   if sys.platform == 'cygwin':
     python_dir = os.path.join(chrome_src, 'third_party', 'python_26')
     env = os.environ.copy()
     env['PATH'] = python_dir + os.pathsep + env.get('PATH', '')
     p = subprocess.Popen(
        [os.path.join(python_dir, 'python.exe')] + sys.argv,
        env=env, shell=False)
@@ skipping 42 matching lines @@
   # to enfore syntax checking.
   syntax_check = os.environ.get('CHROMIUM_GYP_SYNTAX_CHECK')
   if syntax_check and int(syntax_check):
     args.append('--check')
 
   print 'Updating projects from gyp files...'
   sys.stdout.flush()
 
   # Off we go...
   sys.exit(gyp.main(args))