| Age | Commit message (Collapse) | Author |
|---|
|
Initialization code related to collection of per-task "delay" statistics which
measure how long it had to wait for cpu, sync block io, swapping etc. The
collection of statistics and the interface are in other patches. This patch
sets up the data structures and allows the statistics collection to be
disabled through a kernel boot parameter.
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
* x86-64: (83 commits)
[PATCH] x86_64: x86_64 stack usage debugging
[PATCH] x86_64: (resend) x86_64 stack overflow debugging
[PATCH] x86_64: msi_apic.c build fix
[PATCH] x86_64: i386/x86-64 Add nmi watchdog support for new Intel CPUs
[PATCH] x86_64: Avoid broadcasting NMI IPIs
[PATCH] x86_64: fix apic error on bootup
[PATCH] x86_64: enlarge window for stack growth
[PATCH] x86_64: Minor string functions optimizations
[PATCH] x86_64: Move export symbols to their C functions
[PATCH] x86_64: Standardize i386/x86_64 handling of NMI_VECTOR
[PATCH] x86_64: Fix modular pc speaker
[PATCH] x86_64: remove sys32_ni_syscall()
[PATCH] x86_64: Do not use -ffunction-sections for modules
[PATCH] x86_64: Add cpu_relax to apic_wait_icr_idle
[PATCH] x86_64: adjust kstack_depth_to_print default
[PATCH] i386/x86-64: adjust /proc/interrupts column headings
[PATCH] x86_64: Fix race in cpu_local_* on preemptible kernels
[PATCH] x86_64: Fix fast check in safe_smp_processor_id
[PATCH] x86_64: x86_64 setup.c - printing cmp related boottime information
[PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status
...
Manual resolve of trivial conflict in arch/i386/kernel/Makefile
|
|
In timekeeping code, one often does need to use conversion constants. Naming
these leads to code that's easier to understand, showing the reader between
which units the conversion is made.
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Introduces clocksource switching code and the arch generic time accessor
functions that use the clocksource infrastructure.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Modify the update_wall_time function so it increments time using the
clocksource abstraction instead of jiffies. Since the only clocksource driver
currently provided is the jiffies clocksource, this should result in no
functional change. Additionally, a timekeeping_init and timekeeping_resume
function has been added to initialize and maintain some of the new timekeping
state.
[hirofumi@mail.parknet.co.jp: fixlet]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
nsec_t predates ktime_t and has mostly been superseded by it. In the few
places that are left it's better to make it explicit that we're dealing with
64 bit values here.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
alarm() calls the kernel with an unsigend int timeout in seconds. The
value is stored in the tv_sec field of a struct timeval to setup the
itimer. The tv_sec field of struct timeval is of type long, which causes
the tv_sec value to be negative on 32 bit machines if seconds > INT_MAX.
Before the hrtimer merge (pre 2.6.16) such a negative value was converted
to the maximum jiffies timeout by the timeval_to_jiffies conversion. It's
not clear whether this was intended or just happened to be done by the
timeval_to_jiffies code.
hrtimers expect a timeval in canonical form and treat a negative timeout as
already expired. This breaks the legitimate usage of alarm() with a
timeout value > INT_MAX seconds.
For 32 bit machines it is therefor necessary to limit the internal seconds
value to avoid API breakage. Instead of doing this in all implementations
of sys_alarm the duplicated sys_alarm code is moved into a common function
in itimer.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
With David Woodhouse <dwmw2@infradead.org>
select() presently has a habit of increasing the value of the user's
`timeout' argument on return.
We were writing back a timeout larger than the original. We _deliberately_
round up, since we know we must wait at _least_ as long as the caller asks
us to.
The patch adds a couple of helper functions for magnitude comparison of
timespecs and of timevals, and uses them to prevent the various poll and
select functions from returning a timeout which is larger than the one which
was passed in.
The patch also fixes a bug in compat_sys_pselect7(): it was adding the new
timeout value to the old one and was returning that. It should just return
the new timeout value.
(We have various handy timespec/timeval-to-from-nsec conversion functions in
time.h. But this code open-codes it all).
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andi Kleen <ak@muc.de>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: george anzinger <george@mvista.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Here is a series of patches which introduce in total 13 new system calls
which take a file descriptor/filename pair instead of a single file
name. These functions, openat etc, have been discussed on numerous
occasions. They are needed to implement race-free filesystem traversal,
they are necessary to implement a virtual per-thread current working
directory (think multi-threaded backup software), etc.
We have in glibc today implementations of the interfaces which use the
/proc/self/fd magic. But this code is rather expensive. Here are some
results (similar to what Jim Meyering posted before).
The test creates a deep directory hierarchy on a tmpfs filesystem. Then
rm -fr is used to remove all directories. Without syscall support I get
this:
real 0m31.921s
user 0m0.688s
sys 0m31.234s
With syscall support the results are much better:
real 0m20.699s
user 0m0.536s
sys 0m20.149s
The interfaces are for obvious reasons currently not much used. But they'll
be used. coreutils (and Jeff's posixutils) are already using them.
Furthermore, code like ftw/fts in libc (maybe even glob) will also start using
them. I expect a patch to make follow soon. Every program which is walking
the filesystem tree will benefit.
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Remove getnstimestamp() in favor of ktime.h's ktime_get_ts()
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
- convert posix-timers.c to use hrtimers
- remove the now obsolete abslist code
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
- introduce the nsec_t type
- basic nsec conversion routines: timespec_to_ns(), timeval_to_ns(),
ns_to_timespec(), ns_to_timeval().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
add timespec_valid(ts) [returns false if the timespec is denorm]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
style and whitespace cleanup of the rest of time.h.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
clean up the CLOCK_ portions of time.h
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
remove unused CLOCK_ constants from time.h
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
add 'const' to mktime arguments, and clean it up a bit
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
mktime() and set_normalized_timespec() are large inline functions used in many
places: deinline them.
From: George Anzinger, off-by-1 bugfix
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
There are several functions that might seem appropriate for a timestamp:
get_cycles()
current_kernel_time()
do_gettimeofday()
<read jiffies/jiffies_64>
Each has problems with combinations of SMP-safety, low resolution, and
monotonicity. This patch adds a new function that returns a monotonic SMP-safe
timestamp with nanosecond resolution where available.
Changes:
Split timestamp into separate patch
Moved to kernel/time.c
Renamed to getnstimestamp
Fixed unintended-pointer-arithmetic bug
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
It would appear that the timespec normalize code has an off by one error.
Found in three places. Thanks to Ben for spotting.
Signed-off-by: George Anzinger<george@mvista.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Remove these ifdefs - there's no need to have more than one definition of
these multipliers anywhere.
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Clarify the human-time units to jiffies conversion functions by using the
constants in time.h. This makes many of the subsequent patches direct
copies of the current code.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
There is no do_nanosleep function so kill it's declaration in <linux/time.h>.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
This patch corrects a problem that was originally added with the nanosecond
timestamps in stat patch. The problem is that some file systems don't have
enough space in their on disk inode to save nanosecond timestamps, so they
truncate the c/a/mtime to seconds when flushing an dirty node. In core the
inode would have full jiffies granuality.
This can be observed by programs as a timestamp that jumps backwards under
specific loads when an inode is flushed and then reloaded from disk.
The problem was already known when the original patch went in, but it
wasn't deemed important enough at that time. So far there has been only
one report of it causing problems. Now Tridge is worried that it will
break running Excel over samba4 because Excel seems to do very anal
timestamp checking and samba4 will supply 100ns timestamps over the
network.
This patch solves it by putting the time resolution into the superblock of
a fs and always rounding the in core timestamps to that granuality.
This also supercedes some previous ext2/3 hacks to flush the inode less
often when only the subsecond timestamp changes.
I tried to keep the overhead low, in particular it tries to keep divisions
out of fast paths as far as possible.
The patch is quite big but 99% of it is just relatively straight forward
search'n'replace in a lot of fs. Unconverted filesystems will default to a
1ns granuality, but may still show the problem if they continue to use
CURRENT_TIME. I converted all in tree fs.
One possible future extension of this would be to have two time
granualities per superblock - one that specifies the visible resolution,
and the other to specify how often timestamps should be flushed to disk,
which could be tuned with a mount option per fs (e.g. often m/atimes don't
need to be flushed every second). Would be easy to do as an addon if
someone is interested.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
* Add CLOCK_SGI_CYCLE provided by drivers/char/mmtimer
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
POSIX clocks are to be implemented in the following way according
to V3 of the Single Unix Specification:
1. CLOCK_PROCESS_CPUTIME_ID
Implementations shall also support the special clockid_t value
CLOCK_PROCESS_CPUTIME_ID, which represents the CPU-time clock of the
calling process when invoking one of the clock_*() or timer_*()
functions. For these clock IDs, the values returned by clock_gettime() and
specified by clock_settime() represent the amount of execution time of the
process associated with the clock.
2. CLOCK_THREAD_CPUTIME_ID
Implementations shall also support the special clockid_t value
CLOCK_THREAD_CPUTIME_ID, which represents the CPU-time clock of the
calling thread when invoking one of the clock_*() or timer_*()
functions. For these clock IDs, the values returned by clock_gettime()
and specified by clock_settime() shall represent the amount of
execution time of the thread associated with the clock.
These times mentioned are CPU processing times and not the time that has
passed since the startup of a process. Glibc currently provides its own
implementation of these two clocks which is designed to return the time
that passed since the startup of a process or a thread.
Moreover Glibc's clocks are bound to CPU timers which is problematic when the
frequency of the clock changes or the process is moved to a different
processor whose cpu timer may not be fully synchronized to the cpu timer
of the current CPU. This patchset results in a both clocks working reliably.
The patch also implements the access to other the thread and process clocks
of linux processes by using negative clockid's:
1. For CLOCK_PROCESS_CPUTIME_ID: -pid
2. For CLOCK_THREAD_CPUTIME_ID: -(pid + PID_MAX_LIMIT)
This allows
clock_getcpuclockid(pid) to return -pid
and
pthread_getcpuiclock(pid) to return -(pid + PID_MAX_LIMIT)
to allow access to the corresponding clocks.
Todo:
- The timer API to generate events by a non tick based timer is not
usable in its current state. The posix timer API seems to be only
useful at this point to define clock_get/set. Need to revise this.
- Implement timed interrupts in mmtimer after API is revised.
The mmtimer patch is unchanged from V6 and stays as is in 2.6.9-rc3-mm2.
But I expect to update the driver as soon as the interface to setup hardware
timer interrupts is usable.
Single Thread Testing
CLOCK_THREAD_CPUTIME_ID= 0.494140878 resolution= 0.000976563
CLOCK_PROCESS_CPUTIME_ID= 0.494140878 resolution= 0.000976563
Multi Thread Testing
Starting Thread: 0 1 2 3 4 5 6 7 8 9
Joining Thread: 0 1 2 3 4 5 6 7 8 9
0 Cycles= 0 Thread= 0.000000000ns Process= 0.495117441ns
1 Cycles=1000000 Thread= 0.140625072ns Process= 2.523438792ns
2 Cycles=2000000 Thread= 0.966797370ns Process= 8.512699671ns
3 Cycles=3000000 Thread= 0.806641038ns Process= 7.561527309ns
4 Cycles=4000000 Thread= 1.865235330ns Process= 12.891608163ns
5 Cycles=5000000 Thread= 1.604493009ns Process= 11.528326215ns
6 Cycles=6000000 Thread= 2.086915131ns Process= 13.500983475ns
7 Cycles=7000000 Thread= 2.245118337ns Process= 13.947272766ns
8 Cycles=8000000 Thread= 1.604493009ns Process= 12.252935961ns
9 Cycles=9000000 Thread= 2.160157356ns Process= 13.977546219ns
Clock status at the end of the timer tests:
Gettimeofday() = 1097084999.489938000
CLOCK_REALTIME= 1097084999.490116229 resolution= 0.000000040
CLOCK_MONOTONIC= 177.071675109 resolution= 0.000000040
CLOCK_PROCESS_CPUTIME_ID= 13.978522782 resolution= 0.000976563
CLOCK_THREAD_CPUTIME_ID= 0.497070567 resolution= 0.000976563
CLOCK_SGI_CYCLE= 229.967982280 resolution= 0.000000040
PROCESS clock of 1 (init)= 4.833986850 resolution= 0.000976563
THREAD clock of 1 (init)= 0.009765630 resolution= 0.000976563
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
This patch moves some definitions among time.h, times.h, timex.h and
jiffies.h. The purpose is to sort all jiffies related functions to
jiffies.h, to get rid of the cyclic dependency between time.h & timex.h and
to move all #include lines to the start of the header files.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
|
|
Move local version put in tcp_diag.c into time.h
where it belongs. Also, make it smarted about HZ
values math.
Based upon suggestions from Joe Perches <joe@Perches.com>
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
This issue was discussed on lkml and linux-ia64. The patch introduces
"getnstimeofday" and removes all the code scaling gettimeofday to
nanoseoncs. It makes it possible for the posix-timer functions to return
higher accuracy.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
From: William Lee Irwin III <wli@holomorphy.com>
The time conversion functions may have const args, which is in fact useful
for when they are passed const variables as arguments so as to avoid
discarding qualifiers from pointer types warnings. This is a preparatory
cleanup for a minor aio bugfix.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
|
|
Switch all users of MSEC[S]_TO_JIFFIES and JIFFIES_TO_MSEC[S] over to use
jiffies_to_msecs() and msecs_to_jiffies(). Withdraw MSECS_TO_JIFFIES() and
JIFFIES_TO_MSECS() from the kernel API.
|
|
From: Ingo Molnar <mingo@elte.hu>
We have various different implementations of MSEC[S]_TO_JIFFIES and
JIFFIES_TO_MSEC[S]. We recently had a compile-time clash in USB.
Fix all that up.
- The SCTP version was very inefficient. Hopefully this version is accurate
enough.
- Optimise for the HZ=100 and HZ=1000 cases
- This version does round-up, so sleep(9 milliseconds) works OK on 100HZ.
- We still have lots of jiffies_to_msec and msec_to_jiffies implementations.
From: William Lee Irwin III <wli@holomorphy.com>
Optimize the cases where HZ is a divisor of 1000 or vice-versa in
JIFFIES_TO_MSECS() and MSECS_TO_JIFFIES() by allowing the nonvanishing(!)
integral ratios to appear as a parenthesized expressions eligible for
constant folding optimizations.
From: me
Use typesafe inlines for the jiffies-to-millisecond conversion functions.
This means that milliseconds officially takes the type `unsigned int'.
All current callers seem to be OK with that.
Drivers need to be fixed up to use this instead of their private versions.
|
|
From: George Anzinger <george@mvista.com>
The time conversion code is erroring on the side of a bit too small. The
attached patch forces any error to be on the high side. The current code will
convert 1 nanosecond to zero jiffies (standard says that should be 1). It also
is around 1 nanosecond late on each roll to the next jiffie.
I have done some error checks with this patch applied and get the following
errors in PPB ( Parts Per Billion):
HZ nano sec conversion microsecond conversion
1000 315 45
1024 227 40
100 28 317
In all cases the error is on the high side, which means that the final shift
will, most likely, eliminate the error bits.
|
|
From: george anzinger <george@mvista.com>
a) Fixes bug 858 (http://bugme.osdl.org/show_bug.cgi?id=858)
The problem was caused by round off error in calculating the correct
jiffies value in micro seconds to do the round up to jiffies. The fix
is to do the round up AFTER conversion to jiffies, rather than before.
This only affected the timeval to jiffies calculation.
b) Changed the scale values to get the highest possible precision short
of going to full 64-bit math. This is particularly useful in the
scaling of the seconds part of time. The code now computes a trial
value at compile time and adjusts the scaling if the result is less than
32 bits.
c) Adds comments to time.h to remove (I hope) ALL the confusion that
this file use to generate.
|
|
From: Peter Chubb <peterc@gelato.unsw.edu.au>
Currently, do_setitimer() is used in several files, but doesn't appear
in any header. Thus its declaration is repeated in some files, and
its use causes a warning in others (because there is no declaration
present).
This patch:
-- adds a couple of declarations to linux/times.h
-- removes the (now duplicate) declarations from other files.
|
|
(Steven Cole)
|
|
From: Tim Schmielau <tim@physik3.uni-rostock.de>
This patch adds (or fixes) initialization of wall_to_monotonic for a few
more architectures.
This should get rid of the strange uptime>14600 days reports, except on arm
whose arch file layout is too unfamiliar to me.
The patch is blessed by George Anzinger, but untested due to lack of
hardware.
|
|
From: John Stultz, George Anzinger, Eric Piel
There was confusion over the definition of TICK_USEC. TICK_USEC is
supposed to be based on USER_HZ, however a recent change caused TICK_USEC
to be based on HZ. This broke the adjtimex() interface on systems where
USER_HZ != HZ. This patch reverts the change to TICK_USEC, removes an
added mis-use of the value and fixes some incorrect comments that could
lead to this sort of confusion.
Also this patch resolves the related LTP adjtimex failures.
|
|
From: george anzinger <george@mvista.com>
This patch addresses issues of roundoff error in the time keeping and NTP
code as follows:
The conversion of "actual jiffies" to TICK_USEC and then to TICK_NSEC
introduced large errors if jiffies was not a power of 10 (e.g. 1024 for
the ia64). Most of this is avoided by converting directly to TICK_NSEC.
The calculation of MAX_SEC_IN_JIFFIES (the largest timespec or timeval the
kernel will attempt) had overflow problems in the 64-bit machines. We
introduce a different equation for those machines.
The NTP frequency update code was allowing a micro second of error to
accumulate before applying the correction. We change FINEUSEC to FINENSEC
to do the correction as soon as a full nanosecond has accumulated.
The initial calculation of time_freq for NTP had severe roundoff errors for
HZ not a power of 10 (i.e. 1024). A new equation fixes this.
clock_nanosleep is changed to round up to the next jiffie to cover starting
between jiffies.
|
|
From: george anzinger <george@mvista.com>
This patch does the following:
Pushs down the change from timeval to timespec in the settime routines.
Fixes two places where time was set without updating the monotonic clock
offset. (Changes sys_stime() to call do_settimeofday() and changes
clock_warp to do the update directly.) These were bugs!
Changes the uptime code to use the posix_clock_monotonic notion of uptime
instead of the jiffies. This time will track NTP changes and so should be
better than your standard wristwatch (if your using ntp).
Changes posix_clock_monotonic to start at 0 on boot (was set to start at
initial jiffies).
Fixes a bug (never experienced) in timer_create() in posix-timers.c where
we "could" have released timer_id 0 if "id resources" were low.
Adds a test in do_settimeofday() to error out (EINVAL) attempts to use
unnormalized times. This is passed back up to both settimeofday and
posix_setclock().
Warning: Requires changes in .../arch/???/kernel/time.c to change
do_settimeofday() to return an error if time is not normalized and to use a
timespec instead of timeval for its input.
|
|
|
|
From: george anzinger <george@mvista.com>
In the current system (2.5.67) time_spec to jiffies, time_val to
jiffies and the converse (jiffies to time_val and jiffies to
time_spec) all use 1/HZ as the measure of a jiffie. Because of the
inability of the PIT to actually generate an accurate 1/HZ interrupt,
the wall clock is updated with a more accurate value (999848
nanoseconds per jiffie for HZ = 1000). This causes a 1/HZ
interpretation of jiffies based timing to run faster than the wall
clock, thus causing sleeps and timers to expire short of the requested
time. Try, for example:
time sleep 60
This patch changes the conversion routines to use the same value as
the wall clock update code to do the conversions.
The actual math is almost all done at compile time. The run time
conversions require little if any more execution time.
This patch must be applied after the patch I posted earlier today
which fixed the CLOCK_MONOTONIC resolution issue.
|
|
The POSIX CLOCK_MONOTONIC currently has only 1/HZ resolution. Further, it is
tied to jiffies (i.e. is a restatment of jiffies) rather than "xtime" or the
gettimeofday() clock.
This patch changes CLOCK_MONOTONIC to be a restatment of gettimeofday() plus
an offset to remove any clock setting activity from CLOCK_MONOTONIC. An
offset is kept that represents the difference between CLOCK_MONOTONIC and
gettimeofday(). This offset is updated when ever the gettimeofday() clock is
set to back the clock setting change out of CLOCK_MONOTONIC (which by the
standard, can not be set).
With this change CLOCK_REALTIME (a direct restatement of gettimeofday()),
CLOCK_MONOTONIC and gettimeofday() will all tick at the same time and with
the same rate. And all will be affected by NTP adjustments (save those which
actually set the time).
|
|
that we for the initial value ctually want to check only
wrap-around in an "unsigned int".
|
|
From Tim Schmielau <tim@physik3.uni-rostock.de>
Force jiffies to start out at five-minutes-before-wrap. To find
jiffy-wrapping bugs.
|
|
This is version 23 or so of the POSIX timer code.
Internal changelog:
- Changed the signals code to match the new order of things. Also the
new xtime_lock code needed to be picked up. It made some things a lot
simpler.
- Fixed a spin lock hand off problem in locking timers (thanks
to Randy).
- Fixed nanosleep to test for out of bound nanoseconds
(thanks to Julie).
- Fixed a couple of id deallocation bugs that left old ids
laying around (hey I get this one).
- This version has a new timer id manager. Andrew Morton
suggested elimination of recursion (done) and I added code
to allow it to release unused nodes. The prior version only
released the leaf nodes. (The id manager uses radix tree
type nodes.) Also added is a reuse count so ids will not
repeat for at least 256 alloc/ free cycles.
- The changes for the new sys_call restart now allow one
restart function to handle both nanosleep and clock_nanosleep.
Saves a bit of code, nice.
- All the requested changes and Lindent too :).
- I also broke clock_nanosleep() apart much the same way
nanosleep() was with the 2.5.50-bk5 changes.
TIMER STORMS
The POSIX clocks and timers code prevents "timer storms" by
not putting repeating timers back in the timer list until
the signal is delivered for the prior expiry. Timer events
missed by this delay are accounted for in the timer overrun
count. The net result is MUCH lower system overhead while
presenting the same info to the user as would be the case if
an interrupt and timer processing were required for each
increment in the overrun count.
|
|
Add "seqlock" infrastructure for doing low-overhead optimistic reader
locks (writer increments a sequence number, reader verifies that no
writers came in during the critical region, and lots of careful memory
barriers to take care of business).
Make xtime/get_jiffies_64() use this new locking.
|
|
This is the generic part of the start of the compatibility syscall
layer. I think I have made it generic enough that each architecture can
define what compatibility means.
To use this, an architecture must create asm/compat.h and provide
typedefs for (currently) 'compat_time_t', 'struct compat_timeval' and
'struct compat_timespec'.
|
