Re: timers slow (sleep 1 taking five seconds)

[Robert Elz <kre%munnari.OZ.AU@localhost>]

What you're seeing clearly isn't the TSC calibration problem that I
was having, and Michael fixed (but which would not be fixed in 9.2,
so it was a possible source) as what I was seeing was time actually
running slow, and you're clearly not seeing that - just internal
sleep timers running slow.

However, when I switched from using the (miscalibrated) TSC to using
a different timer hardware source, after having started with a badly
running TSC, I did observe behaviour much like you are reporting.

That is, time was running at the right rate, but internal sleeps were
slow - still running at the incorrect frequency.   That was mentioned
somwhere in the "Weird clock behaviour with current (amd64) kernel" thread.

This one I never bothered looking for, as it seemed (to me) likely to be
just a side effect of the miscalibrated TSC, but perhaps not - perhaps there
is some other bug in the internal timing that is being triggered by
something (if I had to guess, now, I'd say perhaps some overflow, just
because of how long your system has been running without a reboot).

I'd also assume this is something in (relatively) new code - clearly in
the 9 series, but I have had older vintage NetBSD systems running much
longer than 90 days without any issues, but I have never really run a
9.x system, except when that was HEAD - the long running systems tend to be
older (early 8 at best), and on HEAD, I tend to reboot much more frequently
to keep up to date.

If this is what it is, a reboot would almost certainly fix things, for a
while - but would also loose the ability to debug what is currently happening.

kre