Re: [PATCH] Dynamic Tick version 050406-1

[Tony Lindgren <tony@atomide.com>]

* Frank Sorenson <frank@tuxrocks.com> [050407 15:21]:
> Frank Sorenson wrote:
> > Tony Lindgren wrote:
> > 
> >>Thanks for trying it out. What kind of hardware do you have? Does it
> >>have HPET? It looks like no suitable timer for dyn-tick is found...
> >>Maybe the following patch helps?
> >>
> >>Tony
> > 
> > 
> > Does 'different crash' qualify as "helping"?  :)
> 
> Update:
> The patch does seem to fix the crash.  This "different crash" I
> mentioned appears to be related to the netconsole I was using (serial
> console produces stairstepping text, netconsole seems to duplicate
> lines--go figure).  Without netconsole, dynamic tick appears to be
> working, so I'm not sure whether this is a netconsole bug or a dynamic
> tick bug.

This might be because time does not run correctly, see below.

> While dynamic tick no longer panics, with dynamic tick, my system slows
> to whatever is slower than a crawl.  It now takes 6 minutes 50 seconds
> to boot all the way up, compared to 1 minute 35 seconds with my 2.6.12
> kernel without the dynamic tick patch.  I'm not sure where this slowdown
> is occurring yet.

I think I have an idea on what's going on; Your system does not wake to
APIC interrupt, and the system timer updates time only on other interrupts.
I'm experiencing the same on a loaner ThinkPad T30.

I'll try to do another patch today. Meanwhile it now should work
without lapic in cmdline.

Tony