Since kernel 2.6.20, the software clock can also be 300 HZ.

diff --git a/man7/time.7 b/man7/time.7
index 8361f1f82f075d5ad5fa0fe48d1d1421d8f35aa9..38e671a8a7e8c2d6956a38353bb6a2d227750ee5 100644 (file)
--- a/man7/time.7
+++ b/man7/time.7
@@ -73,6 +73,9 @@ starting with 2.6.0, HZ was raised to 1000, giving a jiffy of
 0.001 seconds; since kernel 2.6.13, the HZ value is a kernel
 configuration parameter and can be 100, 250 (the default) or 1000,
 yielding a jiffies value of, respectively, 0.01, 0.004, or 0.001 seconds.
+Since kernel 2.6.20, a further frequency is available: 
+300, a number that divides evenly for the common video 
+frame rates (PAL, 25 HZ; NTSC, 30 HZ).
 .SS "The Epoch"
 Unix systems represent time in seconds since the
 .IR Epoch ,