> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
> Behalf Of Ramon van Handel
> Sent: Sunday, July 02, 2000 1:21 PM
> To: [EMAIL PROTECTED]
> Subject: Re: plex86: progress...
>
>
> Hey Kevin,
>
> Great, looks cool !!
Agreed...
>
> > I made some hacks in plex86 (similar to ones I put in bochs
> some time ago)
> > to load a Linux kernel image straight into memory.
>
> I hope you put the hack in a plugin, so it's clean and easy to
> remove again
> later...
>
> > Made some other mods too. Making some progress. Have
> > to wait until I get a little further, and put some pieces
> > back together. But here's a GIF for kicks.
>
> Hope to see CVS changes soon :)
> PS, I asked a while ago whether it wouldn't be possible to make the
> kernel/ directory a bit less messy by moving all of the specific
> emulation stuff into a separate kernel/emulation/ directory, but I
> never did get a reply. So I ask again: would this be possible ?
>
> > BTW, I moved all the other device models from bochs over to
> > plex86 as well.
> >
> > The Linux boot process is getting to the BogoMips calculation
> > part. It's not bombing, just hanging out. Likely the
> > timing of devices that we have in plex86 so far is too
> > hacky. Will look into shaping that up.
>
> I think the problem is the unreliability of the current timing.
> BogoMIPS calculation relies on reliable timing... if timing
> is very unreliable, it doesn't surprise me that it goes wrong.
>
> Let me elaborate: in order for BogoMIPS calibration to work,
> the system needs to work in such a way that every time a unit
> of (PIT) time elapses, a roughly equal amount of instructions
> has been executed (the same instructions, the BogoMIPS loop
> is tight: see /usr/src/linux/arch/i386/lib/delay.c in
> linux 2.2.x).
>
> How are you going to change this easily ? The "shaping up" you
> talk about doesn't sound so straightforward to me... how about
> our previous idea, of adding timing IOCTLs to the kernel module
> and have it do the timing (still isn't easy, but it is a bit
> easier to get good control on timing). Actually, this sounds
> like a rather difficult problem, because this "reliable" timing
> is not the same sort of timing we'd like to use for the rest
> of the VM run, which is a more synchronised-to-the-real-clock
> timing.
>
> -- Ramon
>
May it be possible to let the guest OS BogoMips calculation run straight
through (or nearly so) with the "illusion" of a lower than host clock rate
and then let Plex86 drop back into its normal timing mode? To some extent
we will need to let something like this happen anyway (especially when we
get around to running command.com, and later windows) just to let the VM
come up and let the guest OS establish some sort of APM or ACPI support (to
keep the guest OS system clock from going ape). Just my two cents on the
issue.
Drew Northup, N1XIM
