Hello,
I have attached a patch (1kB) against sysctl.h of 2.4.16. The patch
allocates a new number for a directory /proc/sys/kernel/time.
I use that sysctl in the kernel add-on named PPSkit for some time now
(since 2.2.13). However as the number was never officially allocated, I
had to change it from 42 to 50, and from 50 to 55 for 2.4.16.
Therefore I'd like to allocate the number permanently.
So is there any benefit? Yes, because there's a problem with
adjtimex(). Historically it was a bad design descision to use one
adjtimex() to implement three different routines:
1) adjtime()
2) ntp_adjtime(), ntp_gettime()
3) controlling internal kernel variables like ``tick''
Actually the current implementation is a cul de sac: The current
reference implementation for the NTP routines uses the same bit
patterns as some Linux-specific extensions to adjtimex(). Partially
it's possible to remap the bits in the kernel to do a new
implementation, but sysctl is the better way to do it.
I have implemented sysctl extensions to read/write the ``tick'' and
slew rate of adjtime() (among others) for my new kernel clock model
using nanoseconds (PPSkit-2.0.1). If there's demand to a back-merge to
the main stream sources, plese say what you would like. As the project
was sponsored a little bit recently, I'm willing to donate a few
working hours for that.
The sysctl part looks like this (older kernel):
tick1b:/proc/sys/kernel/time # ll
total 0
dr-xr-xr-x 2 root root 0 Jan 25 08:10 .
dr-xr-xr-x 3 root root 0 Jan 25 08:10 ..
-r--r--r-- 1 root root 0 Jan 25 08:10 pps
-rw-r--r-- 1 root root 0 Jan 25 08:10
rtc_runs_localtime
-rw-r--r-- 1 root root 0 Jan 25 08:10 rtc_update
-rw-r--r-- 1 root root 0 Jan 25 08:10 tickadj
-rw-r--r-- 1 root root 0 Jan 25 08:10 time_tick
-rw-r--r-- 1 root root 0 Jan 25 08:10 timezone
Except for the first entry (experimental for debugging) the contents
are:
0 (rtc_runs_localtime)
660 (rtc_update)
500000 (tickadj [ns])
10000000 (time_tick [ns])
-60 0 (timezone)
IMHO it's time to make a turn in the cul de sac before the truck hits
the end of the road.
Regards
Ulrich
NOTE: Not subscribed to linux-kernel, so make sure that I'll get your
replies...
Index: include/linux/sysctl.h
===================================================================
RCS file: /root/LinuxCVS/Kernel/include/linux/sysctl.h,v
retrieving revision 1.1.1.6
retrieving revision 1.1.1.6.2.1
diff -u -r1.1.1.6 -r1.1.1.6.2.1
--- include/linux/sysctl.h 2001/12/13 18:56:49 1.1.1.6
+++ include/linux/sysctl.h 2001/12/29 14:59:21 1.1.1.6.2.1
@@ -124,8 +124,19 @@
KERN_CORE_USES_PID=52, /* int: use core or core.%pid */
KERN_TAINTED=53, /* int: various kernel tainted flags */
KERN_CADPID=54, /* int: PID of the process to notify on CAD */
+ KERN_TIME=55, /* directory: time */
};
+/* KERN_TIME names: */
+enum
+{
+ KERN_TIME_TIMEZONE=1, /* struct: timezone */
+ KERN_TIME_RTC_UPDATE=2, /* int: rtc_update */
+ KERN_TIME_RTC_RUNS_LOCALTIME=3, /* int: rtc_runs_localtime */
+ KERN_TIME_TIME_TICK=4, /* int: time_tick */
+ KERN_TIME_TICKADJ=5, /* int: tickadj */
+ KERN_TIME_PPS_VAR=99, /* struct pps_var: pps */
+};
/* CTL_VM names: */
enum
-
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This archive was generated by hypermail 2b29 : Thu Jan 31 2002 - 21:00:29 EST