Re: TSC vs. HPET timecounter priority

[Bernd Ernesti <veego%NetBSD.org@localhost>]

On Sun, Aug 12, 2012 at 08:14:50PM -0700, Erik Fair wrote:
[..]

> Until something is written and committed, I suggest an easy change in 
> timecounter
> "quality" for HPET to make it preferred to TSC if both are present.

It took me also a little while to recognize that i have a timecounter issue.
There was no error message from the ntpd that the system has not a stable
clock. Another system didn't syncronize the time with ntp and so i had to
hunt down what is wrong. My resolution was to change sysctl.conf to switch
from tsc to hpet but that takes to find the issue.

What about the following patch?
tc_quality for hpet is set to 2000 so it would have a higher priority.
Using 1500 leave some room for other implementations to have a higher
priority then tsc.

Index: tsc.c
===================================================================
RCS file: /cvsroot/src/sys/arch/x86/x86/tsc.c,v
retrieving revision 1.30
diff -b -u -r1.30 tsc.c
--- tsc.c       8 Aug 2011 17:00:23 -0000       1.30
+++ tsc.c       13 Aug 2012 05:48:41 -0000
@@ -59,7 +59,7 @@
        .tc_get_timecount = tsc_get_timecount,
        .tc_counter_mask = ~0U,
        .tc_name = "TSC",
-       .tc_quality = 3000,
+       .tc_quality = 1500,
 };
 
 void

Bernd