Fix high CPU usage in profiling on MS-Windows.

 src/w32proc.c (timer_loop): Fix code that waits for timer
 expiration, to avoid high CPU usage.

2 files changed, 9 insertions, 4 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index ee7543a2830..7061038fdec 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2012-10-01  Eli Zaretskii  <eliz@gnu.org>
+
+        * w32proc.c (timer_loop): Fix code that waits for timer
+        expiration, to avoid high CPU usage.
+
 2012-10-01  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * fns.c (check_hash_table, get_key_arg, maybe_resize_hash_table)
diff --git a/src/w32proc.c b/src/w32proc.c
index 4c20ca13379..58e6117a7e8 100644
--- a/src/w32proc.c
+++ b/src/w32proc.c
@@ -333,11 +333,11 @@ timer_loop (LPVOID arg)
           Sleep (sleep_time * 1000 / CLOCKS_PER_SEC);
           /* Always sleep past the expiration time, to make sure we
              never call the handler _before_ the expiration time,
-             always slightly after it.  Sleep(0) relinquishes the rest
-             of the scheduled slot, so that we let other threads
-             work.  */
+             always slightly after it.  Sleep(5) makes sure we don't
+             hog the CPU by calling 'clock' with high frequency, and
+             also let other threads work.  */
           while (clock () < expire)
-            Sleep (0);
+            Sleep (5);
         }
 
       if (itimer->expire == 0)