From: john stultz <johnstul@us.ibm.com>
To: lkml <linux-kernel@vger.kernel.org>
Cc: George Anzinger <george@mvista.com>,
frank@tuxrocks.com, Anton Blanchard <anton@samba.org>,
benh@kernel.crashing.org, Nishanth Aravamudan <nacc@us.ibm.com>,
Roman Zippel <zippel@linux-m68k.org>,
Ulrich Windl <ulrich.windl@rz.uni-regensburg.de>
Subject: [RFC][PATCH - 13/13] NTP cleanup: drop time_phase and time_adj add copyright
Date: Wed, 10 Aug 2005 18:38:08 -0700 [thread overview]
Message-ID: <1123724288.32531.9.camel@cog.beaverton.ibm.com> (raw)
In-Reply-To: <1123724180.32531.6.camel@cog.beaverton.ibm.com>
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 (johnstul@us.ibm.com)
+*
+* 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;
}
next prev parent reply other threads:[~2005-08-11 1:38 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-11 1:21 [RFC - 0/13] NTP cleanup work (v. B5) john stultz
2005-08-11 1:23 ` [RFC][PATCH - 1/13] NTP cleanup: Move NTP code into ntp.c john stultz
2005-08-11 1:25 ` [RFC][PATCH - 2/13] NTP cleanup: Move arches to new ntp interfaces john stultz
2005-08-11 1:26 ` [RFC][PATCH - 3/13] NTP cleanup: Remove unused NTP PPS code john stultz
2005-08-11 1:27 ` [RFC][PATCH - 4/13] NTP cleanup: Breakup ntp_adjtimex() john stultz
2005-08-11 1:28 ` [RFC][PATCH - 5/13] NTP cleanup: Break out leapsecond processing john stultz
2005-08-11 1:28 ` [RFC][PATCH - 6/13] NTP cleanup: Clean up ntp_adjtimex() arguement checking john stultz
2005-08-11 1:31 ` [RFC][PATCH - 7/13] NTP cleanup: Cleanup signed shifting logic john stultz
2005-08-11 1:31 ` [RFC][PATCH - 8/13] NTP cleanup: Integrate second_overflow() logic john stultz
2005-08-11 1:33 ` [RFC][PATCH - 9/13] NTP cleanup: Improve NTP variable names john stultz
2005-08-11 1:33 ` [RFC][PATCH - 10/13] NTP cleanup: Use ntp_lock instead of xtime_lock john stultz
2005-08-11 1:35 ` [RFC][PATCH - 11/13] NTP cleanup: Introduce PPM adjustment variables john stultz
2005-08-11 1:36 ` [RFC][PATCH - 12/13] NTP cleanup: cleanup ntp_advance() adjtime code john stultz
2005-08-11 1:38 ` john stultz [this message]
2005-08-16 2:08 ` [RFC][PATCH - 4/13] NTP cleanup: Breakup ntp_adjtimex() john stultz
2005-08-11 2:13 ` [RFC - 0/9] Generic timekeeping subsystem (v. B5) john stultz
2005-08-11 2:14 ` [PATCH 1/9] Timesource management code john stultz
2005-08-11 2:16 ` [PATCH 2/9] Generic timekeeping core subsystem john stultz
2005-08-11 2:18 ` [PATCH 3/9] Generic timekeeping i386 arch specific changes, part 1 john stultz
2005-08-11 2:19 ` [PATCH 4/9] generic timekeeping i386 arch specific changes, part 2 john stultz
2005-08-11 2:20 ` [PATCH 5/9] generic timekeeping i386 arch specific changes, part 3 john stultz
2005-08-11 2:21 ` [PATCH 6/9] generic timekeeping i386 arch specific changes, part 4 john stultz
2005-08-11 2:23 ` [PATCH 7/9] generic timekeeping i386 arch specific changes, part 5 john stultz
2005-08-11 2:24 ` [PATCH 8/9] generic timekeeping i386 arch specific changes, part 6 john stultz
2005-08-11 2:25 ` [PATCH 9/9] generic timekeeping i386 specific timesources john stultz
2005-08-11 2:32 ` [RFC - 0/9] Generic timekeeping subsystem (v. B5) Lee Revell
2005-08-11 2:39 ` john stultz
2005-08-11 2:44 ` Lee Revell
2005-08-11 6:17 ` Ulrich Windl
2005-08-11 2:37 ` [RFC] Cumulative NTP cleanujp and generic timekeeping patch (v B5) john stultz
2005-08-15 22:14 ` [RFC - 0/9] Generic timekeeping subsystem (v. B5) Roman Zippel
2005-08-16 0:10 ` john stultz
2005-08-16 18:25 ` Christoph Lameter
2005-08-16 23:48 ` john stultz
2005-08-17 0:14 ` Christoph Lameter
2005-08-17 0:17 ` john stultz
2005-08-17 0:21 ` Christoph Lameter
2005-08-17 6:08 ` Ulrich Windl
2005-08-17 14:07 ` Christoph Lameter
2005-08-17 0:28 ` Roman Zippel
2005-08-17 1:17 ` john stultz
2005-08-17 7:40 ` Ulrich Windl
2005-08-19 0:27 ` Roman Zippel
2005-08-20 2:32 ` john stultz
2005-08-21 23:19 ` Roman Zippel
2005-08-22 18:57 ` john stultz
2005-08-23 11:30 ` Roman Zippel
2005-08-23 18:52 ` john stultz
2005-08-23 20:51 ` john stultz
2005-08-23 21:34 ` Roman Zippel
2005-08-23 23:14 ` john stultz
2005-08-23 23:54 ` Roman Zippel
2005-08-24 0:29 ` George Anzinger
2005-08-24 20:36 ` john stultz
2005-08-24 23:46 ` George Anzinger
2005-08-25 0:42 ` john stultz
2005-08-25 1:44 ` George Anzinger
2005-08-25 2:13 ` john stultz
2005-08-24 6:34 ` Ulrich Windl
2005-08-24 9:47 ` Roman Zippel
2005-08-24 18:00 ` john stultz
2005-08-24 18:48 ` Roman Zippel
2005-08-24 19:15 ` john stultz
2005-08-24 19:49 ` Roman Zippel
2005-08-24 22:40 ` john stultz
2005-08-25 0:45 ` Roman Zippel
2005-08-25 18:08 ` john stultz
2005-08-17 19:03 ` George Anzinger
2005-08-15 22:12 ` [RFC - 0/13] NTP cleanup work " Roman Zippel
2005-08-15 22:46 ` john stultz
2005-08-17 0:10 ` Roman Zippel
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