On Friday 13 April 2001  2:20 pm, Reinoud Zandijk wrote:
> Hi Chris,
>
> On Fri, 13 Apr 2001, Chris Gilbert wrote:
> > > Pipe Bandwidth is down with the new code:
> > > it was 7.82 Mb/s, it's now 5.98 MB/s
>
> Yikes... this is still low compared to the PIII figures i saw *SOB*

I know, but it's still a 300% increase over the old code of 1.78MB/s

> > Managed to find the problem, we don't enable clockswitching in the kernel
> > (something that we probably should do)  So when the bootloader disables
> > it, we don't reenable it, so the clock speed drops back down to the bus
> > interface clock speed on the first cache miss, ouch, probably worse on a
> > real sa, this being a kinetic the memory is clocked higher (hence lmbench
> > seeing 66MHz)
> >
> > Anyway workaround is to comment out the EQUD on line 809 or search for
> > clockswitching (809 being real lines, not basic lines ;)
>
> Oh ok !!! great ... was just about to investigate if i could reproduce the
> effects for my sensation is that the new bootloader accellerates stuff for
> me.

That'd be tricky without an SA :)

> > Someone should look into the fact we don't enable clockswitching, see if
> > it's just the SA110 that has it or if others (eg SA11x0 do).  I'll do so
> > at some point as it certainly effects me (and there's nothing like that
> > as an incentive)
>
> I think we sure can put it on ... the reason i used it was more to be safe
> for i didnt know if it had side effects and since i dont have a SA i can't
> test the code ... i'll disable it OK? but before we do that... can you
> check if it's still running ok after it is switched on? don't worry about
> SA11x0 ... AFAIK there is no machine capable of running the bootloader
> that uses those processors :)) ... and prolly wont matter anyway.

I'm thinking more along the lines of the kernel should enable it for the SA. 
I prefer the view that the kernel switches it on.  it's turned off in the 
bootloader to give the impression we've just done a reset.  Note though that 
it does appear to be an SA only feature (not in the xscale from what I can 
tell)

Perhaps it should be PR'd and, for now, disabled in the bootloader, I'm just 
wondering if the SA-11x0 ports need it enabled?

Cheers,
Chris