X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=include%2Flinux%2Ftimes.h;h=0c5aa078dad4a2daf0b3523da9ef1b1b072ad147;hb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;hp=ff00f334ffaa4ce984ddcd88598289a1daaa2674;hpb=9213980e6a70d8473e0ffd4b39ab5b6caaba9ff5;p=linux-2.6.git

diff --git a/include/linux/times.h b/include/linux/times.h
index ff00f334f..0c5aa078d 100644
--- a/include/linux/times.h
+++ b/include/linux/times.h
@@ -55,6 +55,26 @@ static inline u64 jiffies_64_to_clock_t(u64 x)
 }
 #endif
 
+static inline u64 nsec_to_clock_t(u64 x)
+{
+#if (NSEC_PER_SEC % USER_HZ) == 0
+	do_div(x, (NSEC_PER_SEC / USER_HZ));
+#elif (USER_HZ % 512) == 0
+	x *= USER_HZ/512;
+	do_div(x, (NSEC_PER_SEC / 512));
+#else
+	/*
+         * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
+         * overflow after 64.99 years.
+         * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
+         */
+	x *= 9;
+	do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2))
+	                          / USER_HZ));
+#endif
+	return x;
+}
+
 struct tms {
 	clock_t tms_utime;
 	clock_t tms_stime;