All,
This patch replaces two global variables with better named static local
variables. Additionally it adds my copyright.
Any comments or feedback would be greatly appreciated.
thanks
-john
linux-2.6.13-rc6_timeofday-ntp-part13_B5.patch
============================================
diff --git a/kernel/ntp.c b/kernel/ntp.c
--- a/kernel/ntp.c
+++ b/kernel/ntp.c
@@ -3,7 +3,9 @@
*
* NTP state machine and time scaling code.
*
-* Code moved from kernel/time.c and kernel/timer.c
+* Copyright (C) 2004, 2005 IBM, John Stultz ([email protected])
+*
+* Code moved and rewritten from kernel/time.c and kernel/timer.c
* Please see those files for original copyrights.
*
* This program is free software; you can redistribute it and/or modify
@@ -48,8 +50,6 @@
/* Don't completely fail for HZ > 500. */
int tickadj = 500/HZ ? : 1; /* microsecs */
-static long time_phase; /* phase offset (scaled us) */
-static long time_adj; /* tick adjust (scaled 1 / HZ) */
/* Chapter 5: Kernel Variables [RFC 1589 pg. 28] */
/* 5.1 Interface Variables */
@@ -86,9 +86,9 @@ static seqlock_t ntp_lock = SEQLOCK_UNLO
void ntp_advance(unsigned long interval_nsec)
{
static unsigned long interval_sum = 0;
- long time_adjust_step;
unsigned long flags;
static long ss_adj = 0;
+ static long phase, phase_adj = 0;
write_seqlock_irqsave(&ntp_lock, flags);
@@ -128,22 +128,24 @@ void ntp_advance(unsigned long interval_
ntp_offset -= next_adj;
offset_adj = shiftR(next_adj, SHIFT_UPDATE); /* ppm */
- time_adj = next_adj << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
- time_adj += shiftR(ntp_freq, (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE));
+ /* calculate the per tick phase adjustment for the next second */
+ phase_adj = next_adj << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+ phase_adj += shiftR(ntp_freq, (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE));
#if HZ == 100
/* Compensate for (HZ==100) != (1 << SHIFT_HZ).
* Add 25% and 3.125% to get 128.125;
* => only 0.125% error (p. 14)
*/
- time_adj += shiftR(time_adj,2) + shiftR(time_adj,5);
+ phase_adj += shiftR(phase_adj,2) + shiftR(phase_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)
*/
- time_adj += shiftR(time_adj,6) + shiftR(time_adj,7);
+ phase_adj += shiftR(phase_adj,6) + shiftR(phase_adj,7);
#endif
+
/* Set ss_adj for the next second */
ss_adj = min_t(unsigned long, singleshot_adj, MAX_SINGLESHOT_ADJ);
singleshot_adj -= ss_adj;
@@ -176,14 +178,14 @@ void ntp_advance(unsigned long interval_
* Advance the phase, once it gets to one nanosecond,
* then advance the fixed_tick_ns_adj.
*/
- time_phase += time_adj;
- if (time_phase <= -FINENSEC) {
- long ltemp = -time_phase >> (SHIFT_SCALE - 10);
- time_phase += ltemp << (SHIFT_SCALE - 10);
+ phase += phase_adj;
+ if (phase <= -FINENSEC) {
+ long ltemp = -phase >> (SHIFT_SCALE - 10);
+ phase += ltemp << (SHIFT_SCALE - 10);
fixed_tick_ns_adj -= ltemp;
- } else if (time_phase >= FINENSEC) {
- long ltemp = time_phase >> (SHIFT_SCALE - 10);
- time_phase -= ltemp << (SHIFT_SCALE - 10);
+ } else if (phase >= FINENSEC) {
+ long ltemp = phase >> (SHIFT_SCALE - 10);
+ phase -= ltemp << (SHIFT_SCALE - 10);
fixed_tick_ns_adj += ltemp;
}
-
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