Re: slow screen updates on laptop console (i386)

From: Rick Macklem <rmacklem_at_uoguelph.ca>
Date: Tue, 8 Dec 2015 15:52:08 -0500 (EST)
John Baldwin wrote:
> On Monday, December 07, 2015 06:01:08 PM Rick Macklem wrote:
> > Adrian Chadd wrote:
> > > Hi,
> > > 
> > > ok. please file a bug for that. It may be something to do with the
> > > hardware and sleep states and skipping wakeups/interrupts or
> > > something.
> > > 
> > > Please try using the default again (LAPIC?) and set
> > > kern.eventtimer.periodic=1. See if that fixes it.
> > > 
> > Actually made it worse. Instead of being intermittently slow, it was
> > almost constantly slow.
> 
> Try disabling C-states if they are enabled.  If you have a BIOS option
> for C1E you might need to disable that as well.  If this fixes it, then
> there isn't a really viable solution in software, and you might prefer
> to use the RTC to get the power savings from C-states.
> 
Well, if the above refers to stuff that would be in the BIOS setup, there
isn't anything. Nothing setable w.r.t. the processor and there isn't much
of anything under power savings either (a couple of auto-boot options).
- It's a single core i386 Celeron about 8 years old.
(On the other hand, if these C states are something the FreeBSD kernel sets,
 then I don't know how it's done;-)

Btw, I'm perfectly happy running it with RTC. It was Adrian that was interested
in investigating it more.

Thanks, rick

> --
> John Baldwin
> 
Received on Tue Dec 08 2015 - 19:52:17 UTC

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