linux-toradex.git/include/linux/timex.h, branch tegra-9.12.15

time: move PIT_TICK_RATE to linux/timex.h

2009-06-17T02:47:27+00:00

PIT_TICK_RATE is currently defined in four architectures, but in three
different places.  While linux/timex.h is not the perfect place for it, it
is still a reasonable replacement for those drivers that traditionally use
asm/timex.h to get CLOCK_TICK_RATE and expect it to be the PIT frequency.

Note that for Alpha, the actual value changed from 1193182UL to 1193180UL.
 This is unlikely to make a difference, and probably can only improve
accuracy.  There was a discussion on the correct value of CLOCK_TICK_RATE
a few years ago, after which every existing instance was getting changed
to 1193182.  According to the specification, it should be
1193181.818181...

Signed-off-by: Arnd Bergmann 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Len Brown 
Cc: john stultz 
Cc: Dmitry Torokhov 
Cc: Takashi Iwai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ntp: fix comment typos

2009-05-12T08:35:15+00:00

Bernhard Schiffner noticed I had a few comment typos in this patch,
(note: to save embarrassment, when making typos, avoid copying and
pasting them) so this patch corrects them.

[ Impact: cleanup ]

Reported-by: Bernhard Schiffner 
Signed-off-by: John Stultz 
Cc: riel@redhat.com
Cc: akpm@linux-foundation.org
LKML-Reference: <1242090794.7214.131.camel@localhost.localdomain>
Signed-off-by: Ingo Molnar

ntp: adjust SHIFT_PLL to improve NTP convergence

2009-05-06T09:44:02+00:00

The conversion to the ntpv4 reference model
f19923937321244e7dc334767eb4b67e0e3d5c74 ("ntp: convert to the NTP4
reference model") in 2.6.19 added nanosecond resolution the adjtimex
interface, but also changed the "stiffness" of the frequency adjustments,
causing NTP convergence time to greatly increase.

SHIFT_PLL, which reduces the stiffness of the freq adjustments, was
designed to be inversely linked to HZ, and the reference value of 4 was
designed for Unix systems using HZ=100.  However Linux's clock steering
code mostly independent of HZ.

So this patch reduces the SHIFT_PLL value from 4 to 2, which causes NTPd
behavior to match kernels prior to 2.6.19, greatly reducing convergence
times, and improving close synchronization through environmental thermal
changes.

The patch also changes some l's to L's in nearby code to avoid misreading
50l as 501.

[ Impact: tweak NTP algorithm for faster convergence ]

Signed-off-by: John Stultz 
Acked-by: Rik van Riel 
Cc: zippel@linux-m68k.org
Signed-off-by: Andrew Morton 
LKML-Reference: <200905051956.n45JuVo9025575@imap1.linux-foundation.org>
Signed-off-by: Ingo Molnar

time: ntp: make 64-bit constants more robust

2009-02-25T17:38:15+00:00

Impact: cleanup, no functionality changed

 - make PPM_SCALE an explicit s64 constant, to
   remove (s64) casts from usage sites.

kernel/time/ntp.o:

   text	   data	    bss	    dec	    hex	filename
   2536	    114	    136	   2786	    ae2	ntp.o.before
   2536	    114	    136	   2786	    ae2	ntp.o.after

md5:
   40a7728d1188aa18e83e21a81fa7b150  ntp.o.before.asm
   40a7728d1188aa18e83e21a81fa7b150  ntp.o.after.asm

Signed-off-by: Ingo Molnar

linux/timex.h: cleanup for userspace

2008-12-12T16:01:38+00:00

Impact: fix user-space exported use

Move all the kernel-specific defines and includes into the __KERNEL__
section so that they don't get leaked into userspace.

[akpm@linux-foundation.org: coding-style fixes]

Signed-off-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner

ntp: improve adjtimex frequency rounding

2008-09-24T15:33:13+00:00

Change PPM_SCALE_INV_SHIFT so that it doesn't throw away any input bits
(19 is the amount of the factor 2 in PPM_SCALE), the output frequency
can then be calculated back to its input value, as the inverse divide
produce a slightly larger value, which is then correctly rounded by the
final shift.

Reported-by: Martin Ziegler 
Signed-off-by: Roman Zippel 
Cc: John Stultz 
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner

ntp: fix ADJ_OFFSET_SS_READ bug and do_adjtimex() cleanup

2008-08-22T04:40:18+00:00

Thanks to the review by Michael Kerrisk a bug in the recent
ADJ_OFFSET_SS_READ option was discovered, where the ntp time_offset was
inadvertently set by it.  This fixes this by making the adjtime code
more separate from the ntp_adjtime code (both of which really want to
be separate syscalls).

Signed-off-by: Roman Zippel 
Signed-off-by: Andrew Morton 
Acked-by: John Stultz 
Signed-off-by: Ingo Molnar

ntp: handle leap second via timer

2008-05-01T15:03:59+00:00

Remove the leap second handling from second_overflow(), which doesn't have to
check for it every second anymore.  With CONFIG_NO_HZ this also makes sure the
leap second is handled close to the full second.  Additionally this makes it
possible to abort a leap second properly by resetting the STA_INS/STA_DEL
status bits.

Signed-off-by: Roman Zippel 
Cc: john stultz 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ntp: remove current_tick_length()

2008-05-01T15:03:59+00:00

current_tick_length used to do a little more, but now it just returns
tick_length, which we can also access directly at the few places, where it's
needed.

Signed-off-by: Roman Zippel 
Cc: john stultz 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ntp: rename TICK_LENGTH_SHIFT to NTP_SCALE_SHIFT

2008-05-01T15:03:59+00:00

As TICK_LENGTH_SHIFT is used for more than just the tick length, the name
isn't quite approriate anymore, so this renames it to NTP_SCALE_SHIFT.

Signed-off-by: Roman Zippel 
Cc: john stultz 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds