system time running out - again

Hi all!

Some time ago, people in this list notified a problem with the system 
time (see in 
http://www2.fsmlabs.com/pipermail/rtl/2005-February/030056.html).

After some messages, was identified three problems:

1 - A minor error in the HZ variable in include/asm-i368/param.h (the HZ 
variable was seted with 1000. However, the correct value is 100). This 
correction was applied.
2 -  "the interrupts emulation was changed to trigger the linux side 
unconditionally which was a hack to kick soft-irq with a low latency 
independent from the   occurance of hardware interrupts, and secondly 
the pending of irqs to linux unconditionally to allow sharing of irqs".  
I can't check in the list if this problem was solved or not.
3  - The definition of CLOCK_TICK_RATE (include/asm-i386/timex.h) in AMD 
Boxes seems to be 1189200 instead 1193100. The value of CLOCK_TICK_RATE 
was changed to 1189200 for all CPU configs. This correction was applied.

I use the kernel 2.4.29 with the current rtl3.2-rc1 from cvs in my boxes.

For my surprise, I observe which the system time is running to fast. To 
check this, I adjust the system time with the ntp server 200.20.186.75. 
After 10 minutes, the error with this server is more than 2s. It is a 
great offset in a small time. Following below the ntpdate output:

26 Dec 16:53:13 ntpdate[7757]: adjust time server 200.20.186.75 offset 
-8.465980 sec
after 10min:
26 Dec 17:03:51 ntpdate[7764]: adjust time server 200.20.186.75 offset 
-2.119054 sec

I checks this times with 2 Intel machines (a P4HT and a Celeron D 
Boxes), with the same kernel configs (PIII processor in config, with 
local APIC, IO APIC, Unsynced TSC support, APM and ACPI configured). The 
results are alike.

After that, I recompile the kernel with the CLOCK_TICK_RATE seted with 
1193182 (the value is found in the timex.h from kernel 2.6 tree).
The results are the same in the two boxes. See the ntpdate output:

26 Dec 17:44:32 ntpdate[18590]: adjust time server 200.20.186.75 offset 
-0.015455 sec
after 10 min:
26 Dec 17:54:56 ntpdate[18726]: step time server 200.20.186.75 offset 
-2.059203 sec.
and after ~22min:
26 Dec 18:16:50 ntpdate[18749]: step time server 200.20.186.75 offset 
-4.354148 sec

I check the error in the CLOCK_REALTIME and the CLOCK_GPOS in both 
situations. The error is +/- 32ns in almost cases. Both the clocks is 
run much faster than I expected.

Someone have any comments or same results with your configurations in 
your boxes?

Comments may be very useful!

Best regards,
-- 
Robson Sales

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