Messages in this thread | | | From | "Ulrich Windl" <> | Date | Wed, 3 Feb 1999 08:45:33 +0100 | Subject | announce: 2.2.1: kernel time changes (experimental patch) |
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Hello,
being tired of having a bug-free kernel? ;-)
I have an experimental patch that is a snapshot from the yet-to-come PPSkit-0.5. As great things are planned, I thought I'd correct the basics first:
I have moved the time related stuff from kernel/sched.c to kernel/time.c (where it always belonged, but never appeared). The same is true for sched.h and time.h. Interestingly compilation of my i386 kernel showed that no file had to be changed, even though xtime is only declared in <linux/time.h> now (meaning that all the files using <time.h> also used <sched.h>).
In addition I made the NTP stuff optional for small kernels or embedded systems that do not need/want it. There are now three levels for NTP/PPS support:
1) CONFIG_NTP 2) CONFIG_NTP_PPS 3) CONFIG_NTP_PPS_SERIAL
For compatibility with standard kernels CONFIG_NTP should be set. In previous PPSkits 2) and 3) simply wre CONFIG_PPS_SYNC. Now you can have the basic PPS functions in the kernel, and still having an unchanged serial driver if you like (by setting only 2)). If anyone wants to write PPS code for some other exotic device (like the parallel port) it could be done with CONFIG_NTP_PPS_<other>. I hope that the concept is clear enough now.
I'd like people to try this patch, even if they disable everything, because I have only build two kernels on a i386 with everything ENABLED. Maybe other achitectures or drivers I don't use have a problem. Please tell me what is wrong!
Linus basically likes the idea to move the time stuff out from sched.c (sched.c is much shorter now), and maybe others will like the optional NTP stuff. If people like the idea very much, and if Linus agrees, I could rip out another portion of the future PPSkit to be included in the standard kernel, maybe even in 2.2.x.
One well-known bug/feature: adjtimex() _silently_ ignores mode values it doesn't know about. So if you disable NTP stuff in the kernel, you still can run applications using it, but they will silently fail. I want to resolve this too, soon.
As the next generation of NTP support in the kernel will use 64bit quantities, the NTP overhead might be noticable. Therefore I first wanted to make it optional.
(The PPSkit functionality basically corresponds to PPSkit-0.4.2 with fixes included)
For those located at master.kernel.org, the stuff (PPSkit-0.5.0- pre1.diff.gz) is located in ~windl; others have a look at ftp://pcphy4.physik.uni-regensburg.de/pub/wiu09524/PPS
The patch is 18kB...
Regards, Ulrich Windl
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