* missing #if for 1000 HZ
@ 2003-07-23 1:01 Albert Cahalan
0 siblings, 0 replies; only message in thread
From: Albert Cahalan @ 2003-07-23 1:01 UTC (permalink / raw)
To: linux-kernel, Ulrich.Windl; +Cc: Andrew Morton, alan
This should improve timekeeping a bit @ 1000 HZ.
diff -Naurd old/kernel/timer.c new/kernel/timer.c
--- old/kernel/timer.c 2003-07-18 17:27:01.000000000 -0400
+++ new/kernel/timer.c 2003-07-18 17:32:19.000000000 -0400
@@ -606,6 +606,15 @@
else
time_adj += (time_adj >> 2) + (time_adj >> 5);
#endif
+#if HZ == 1000
+ /* Compensate for (HZ==1000) != (1 << SHIFT_HZ).
+ * Add 1.5625% and 0.78125% to get 1023.4375; => only 0.05% error (p. 14)
+ */
+ if (time_adj < 0)
+ time_adj -= (-time_adj >> 6) + (-time_adj >> 7);
+ else
+ time_adj += (time_adj >> 6) + (time_adj >> 7);
+#endif
}
/* in the NTP reference this is called "hardclock()" */
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2003-07-23 1:01 missing #if for 1000 HZ Albert Cahalan
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