Re: Still seeing "calcru: runtime went backwards" messages

On 3/2/06, Poul-Henning Kamp <phk_at_phk.freebsd.dk> wrote:
> In message <200603011724.08214.jhb_at_freebsd.org>, John Baldwin writes:
>
> >Maybe we could make the dynamic flag for the tsc controllable via tunable?
>
> Ideally ACPI would tell us the max TSC frequency and the TSC wouldn't need
> to be marked variable. Havn't had time to look at this yet though.
>
> >If I have a server machine without any fancy pentium-m cpufreq type stuff,
> >then I would rather just use the tsc frequency snapshot taken at boot and
> >just stick with that as the static frequency then have a bunch of warnings
> >on the console if the max freq changes sometime later.
>
> Right, I would actually prefer to try to make the calibration more precise
> first, rather than add yet another knob for roots to remember to tweak.
>
> >Also, note that
> >I am still getting a bunch of the backwards messages on my DS20 Alpha which
> >is _not_ using the TSC. :)
>
> That's interesting...  Alpha should be using the timecounter and that
> is not marked "variable".
>
> My alpha hasn't been able to boot in a long time now :-(
>
> > (I should probably fix Alpha to use its own
> >version of the TSC at some point, but for now I want to get it to stop
> >spitting out the warnings when using the timecounters as that shouldn't
> >be causing any warnings).
>
> I'd be tempted to just supress the warning if the negative delta is less
> than 3usec (for some value of 3).

Could not one put in a counter variable and only print the message
every 50 times it happens (for some value of 50)?

Ben Kaduk