speed up jiffies conversion functions if HZ==USER_HZ
Andrew Morton [Wed, 6 Feb 2008 09:38:06 +0000 (01:38 -0800)]
Avoid calling do_div(x, 1) in this case.

Cc: David Fries <david@fries.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/time.c

index be5c8cb..33af3e5 100644 (file)
@@ -606,8 +606,10 @@ u64 jiffies_64_to_clock_t(u64 x)
 # if HZ < USER_HZ
        x *= USER_HZ;
        do_div(x, HZ);
-# else
+# elif HZ > USER_HZ
        do_div(x, HZ / USER_HZ);
+# else
+       /* Nothing to do */
 # endif
 #else
        /*