sysclock_getsnapshot() function allows the caller to obtain a snapshot of all
the system clock and timecounter state required to create time stamps at a later
point. The sysclock_snap2bintime() function converts a previously obtained
snapshot into a bintime time stamp according to the specified flags e.g. which
system clock, uptime vs absolute time, etc.
These KPIs enable useful functionality, including direct comparison of the
feedback and feed-forward system clocks and generation of multiple time stamps
with different formats from a single timecounter read.
Committed on behalf of Julien Ridoux and Darryl Veitch from the University of
Melbourne, Australia, as part of the FreeBSD Foundation funded "Feed-Forward
Clock Synchronization Algorithms" project.
For more information, see http://www.synclab.org/radclock/
In collaboration with: Julien Ridoux (jridoux at unimelb edu au)
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.
Reviewed by: rwatson
Approved by: re (bz)
PMC/SYSV/...).
No FreeBSD version bump, the userland application to query the features will
be committed last and can serve as an indication of the availablility if
needed.
Sponsored by: Google Summer of Code 2010
Submitted by: kibab
Reviewed by: arch@ (parts by rwatson, trasz, jhb)
X-MFC after: to be determined in last commit with code from this project
SI_SUB_RUN_SCHEDULER+SI_ORDER_ANY should only be used to call
scheduler() function which turns the initial thread into swapper proper
and thus there is no further SYSINIT processing.
Other SYSINITs with SI_SUB_RUN_SCHEDULER+SI_ORDER_ANY may get ordered
after scheduler() and thus never executed. That particular relative
order is semi-arbitrary.
Thus, change such places to use SI_ORDER_MIDDLE.
Also, use SI_ORDER_MIDDLE instead of correct, but less appealing,
SI_ORDER_ANY - 1.
MFC after: 1 week
This is done in kern_ntptime, perhaps not the best place.
This is done using resettodr().
Some features:
- make save period configurable via tunable and sysctl
- period of zero disables saving, setting a non-zero period re-enables
it or reschedules it
- do saving only if system clock is ntp-synchronized
- save on shutdown
Discussed with: des, Peter Jeremy <peterjeremy@acm.org>
X-Maybe: save time near seconds boundary for better precision
MFC after: 2 weeks
after each SYSINIT() macro invocation. This makes a number of
lightweight C parsers much happier with the FreeBSD kernel
source, including cflow's prcc and lxr.
MFC after: 1 month
Discussed with: imp, rink
- Remove also "MP SAFE" after prior "MPSAFE" pass. (suggested by bde)
- Remove extra blank lines in some cases.
- Add extra blank lines in some cases.
- Remove no-op comments consisting solely of the function name, the word
"syscall", or the system call name.
- Add punctuation.
- Re-wrap some comments.
system calls now enter without Giant held, and then in some cases, acquire
Giant explicitly.
Remove a number of other MPSAFE annotations in the credential code and
tweak one or two other adjacent comments.
call, its semantics were unintentionally changed. It went from
returning the time state to returning 0 or -1. Since 0 means time
normal, and non-zero effectively only shows up around leap seconds,
this went unnoticed until now. At least unnoticed until someone was
trying to run a binary they didn't have source for and it was
misbehaving...
Submitted by: Judah Levine
MFC After: 2 weeks
specific privilege names to a broad range of privileges. These may
require some future tweaking.
Sponsored by: nCircle Network Security, Inc.
Obtained from: TrustedBSD Project
Discussed on: arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
Alex Lyashkov <umka at sevcity dot net>,
Skip Ford <skip dot ford at verizon dot net>,
Antoine Brodin <antoine dot brodin at laposte dot net>
sysctl path. While this code is close to MPSAFE, it may require some
additional locking. Mark ntp_gettime1() as GIANT_REQUIRED for now.
Suggested by: phk
one which runs the actual update. This fixes a bug where there were
a delay in applying the frequency adjustment. In extreme cases this
could result in marginal stability of the kernel-pll.
incremented at the start of the leap second, not after the leap second
has been inserted. This is because at the start of the leap second,
we set the time back one second. This setting back one second is the
moment that the offset changes. The old code set it back after the
leap second, but that's one second too late. The negative leap second
case is handled correctly.
Reviewed by: phk
called. Otherwise (depending on a non-deterministic sort), the timecounter
code can be initialized before the clock rate has been set (on ia64) and it
assumes hz = 100, rather than the real value of 1024. I'm not sure how much
gets upset by this.
Glanced at by: phk
Apply the change as a continuous slew rather than as a series of
discrete steps and make it possible to adjust arbitraryly huge
amounts of time in either direction.
In practice this is done by hooking into the same once-per-second
loop as the NTP PLL and setting a suitable frequency offset deducting
the amount slewed from the remainder. If the remaining delta is
larger than 1 second we slew at 5000PPM (5msec/sec), for a delta
less than a second we slew at 500PPM (500usec/sec) and for the last
one second period we will slew at whatever rate (less than 500PPM)
it takes to eliminate the delta entirely.
The old implementation stepped the clock a number of microseconds
every HZ to acheive the same effect, using the same rates of change.
Eliminate the global variables tickadj, tickdelta and timedelta and
their various use and initializations.
This removes the most significant obstacle to running timecounter and
NTP housekeeping from a timeout rather than hardclock.
general cleanup of the API. The entire API now consists of two functions
similar to the pre-KSE API. The suser() function takes a thread pointer
as its only argument. The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0. The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.
Discussed on: smp@
The binary format "bintime" is a 32.64 format, it will go to 64.64
when time_t does.
The bintime format is available to consumers of time in the kernel,
and is preferable where timeintervals needs to be accumulated.
This change simplifies much of the magic math inside the timecounters
and improves the frequency and time precision by a couple of bits.
I have not been able to measure a performance difference which was not
a tiny fraction of the standard deviation on the measurements.
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
Make the public interface more systematically named.
Remove the alternate method, it doesn't do any good, only ruins performance.
Add counters to profile the usage of the 8 access functions.
Apply the beer-ware to my code.
The weird +/- counts are caused by two repocopies behind the scenes:
kern/kern_clock.c -> kern/kern_tc.c
sys/time.h -> sys/timetc.h
(thanks peter!)
hardpps() produced offset component. This is tested and behaved
stable with frequency offsets from -338.05 to +499.91 PPM.
Interestingly the machine I tested this on would fail if the clock
were slower than 14.3132 MHz whereas it was perfectly happy to run
at 16.384 MHz, in other words [-340PPM ... +14.4%]
Make pps_shift tweakable with sysctl.
resulted in vastly optimistic offset values reported to userland
(typically a factor 40+ too small). Apart from that, the code had
two sign-bugs.
Apply the hardpps() phase with the right sign with a simply
scaling by integration interval. (This may be too stiff at
long integration intervals, see below).
Allow pps_shiftmax to be reduced again.
Before this, the phase lock in hardpps() were broken, but due to
two bugs mostly cancelling out, it would end up basically working
with a large stochastic component. Now it behaves as one would
expect: smooth and quiet.
It seems that pps_shiftmax above 7..9 somewhere makes the phaselock
too weak to hold onto random walk phase errors from a HP-105 OCXO,
which basically means that it is too weak for real-life use with
such integration times. This is yet to be resolved.
Submitted to: Prof. Dave "NTP" Mills.
Tested by: Terje Mathisen <Terje.Mathisen@hda.hydro.com>
1:
s/suser/suser_xxx/
2:
Add new function: suser(struct proc *), prototyped in <sys/proc.h>.
3:
s/suser_xxx(\([a-zA-Z0-9_]*\)->p_ucred, \&\1->p_acflag)/suser(\1)/
The remaining suser_xxx() calls will be scrutinized and dealt with
later.
There may be some unneeded #include <sys/cred.h>, but they are left
as an exercise for Bruce.
More changes to the suser() API will come along with the "jail" code.
