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Diffstat (limited to 'usr.sbin/xntpd/doc/tickadj.8')
-rw-r--r-- | usr.sbin/xntpd/doc/tickadj.8 | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/usr.sbin/xntpd/doc/tickadj.8 b/usr.sbin/xntpd/doc/tickadj.8 new file mode 100644 index 0000000..5fce088 --- /dev/null +++ b/usr.sbin/xntpd/doc/tickadj.8 @@ -0,0 +1,143 @@ +''' $Header +''' +.de Sh +.br +.ne 5 +.PP +\fB\\$1\fR +.PP +.. +.de Sp +.if t .sp .5v +.if n .sp +.. +.de Ip +.br +.ie \\n.$>=3 .ne \\$3 +.el .ne 3 +.IP "\\$1" \\$2 +.. +''' +''' Set up \*(-- to give an unbreakable dash; +''' string Tr holds user defined translation string. +''' Bell System Logo is used as a dummy character. +''' +.tr \(bs-|\(bv\*(Tr +.ie n \{\ +.ds -- \(bs- +.if (\n(.H=4u)&(1m=24u) .ds -- \(bs\h'-12u'\(bs\h'-12u'-\" diablo 10 pitch +.if (\n(.H=4u)&(1m=20u) .ds -- \(bs\h'-12u'\(bs\h'-8u'-\" diablo 12 pitch +.ds L" "" +.ds R" "" +.ds L' ' +.ds R' ' +'br\} +.el\{\ +.ds -- \(em\| +.tr \*(Tr +.ds L" `` +.ds R" '' +.ds L' ` +.ds R' ' +'br\} +.TH TICKADJ 8 LOCAL +.SH NAME +tickadj - fiddle time\-related variables in the kernel +.SH SYNOPSIS +.B tickadj +[ +.B -Aqs +] [ +.B -a +.I new_tickadj +] [ +.B -t +.I new_tick +] +.SH DESCRIPTION +The +.I tickadj +program reads, and optionally modifies, several time\-keeping\-related +variables in the running kernel, via +.IR /dev/kmem . +The particular variables it is concerned with are +.IR tick , +which is the number of microseconds added to the system time during a +clock interrupt, +.IR tickadj , +which sets the slew rate and resolution used by the +.IR adjtime (2) +system call, and +.IR dosynctodr , +which indicates to the kernels on some machines whether they should internally +adjust the system clock to keep it in line with with time\-of\-day clock +or not. +.PP +By default, with no arguments, +.I tickadj +reads the variables of interest in the kernel and prints them. At the +same time it determines an \*(L"optimal\*(R" value for the value of the +.I tickadj +variable if the intent is to run the +.IR xntpd (8) +Network Time Protocol daemon, and prints this as well. Since the operation +of +.I tickadj +when reading the kernel mimics the operation of similar parts of the +.IR xntpd (8) +program fairly closely, this is useful for doing debugging of problems +with +.IR xntpd (8). +.PP +Various flags may be specified to change the variables of interest in +the running kernel. The +.B -a +flag allows one to set the the variable +.I tickadj +to the value specified as an argument. The +.B -A +flag will also cause +.I tickadj +to be modified, but instead will set it to the internally computed +\*(L"optimal\*(R" value. The +.B -t +flag may be used to reset the kernel's value of +.IR tick , +a capability which is useful on machines with very broken clocks. The +.B -s +flag tells the program to set the value of the variable +.I dosynctodr +to zero, a prerequisite for running the +.IR xntpd (8) +daemon under SunOS 4.0. Normally +.I tickadj +is quite verbose about what it is doing. The +.B -q +flag tells it to shut up about everything except errors. +.PP +Note that +.I tickadj +should be run with some caution when being used for the first time on +different types of machines. The operations which +.I tickadj +trys to perform are not guaranteed to work on all Unix machines. +.SH FILES +.nf +/vmunix +/unix +/dev/kmem +.fi +.SH SEE ALSO +xntpd(8) +.SH HISTORY +Written by Dennis Ferguson at the University of Toronto +.SH BUGS +Fiddling with kernel variables at run time as a part of ordinary +operations is a hideous practice which is only necessary to make +up for deficiencies in the implementation of +.IR adjtime (8) +in many kernels and/or brokenness of the system clock in some +vendors' kernels. It would be much better if the kernels were fixed +and the +.I tickadj +program went away. |