Re: NetBSD/vax - worth continuing?

[Anders Magnusson <ragge%ludd.ltu.se@localhost>]

> After lots of experimentation and playing around, I think the problem 
> is not related to loosing buffers. I'll try to explain my 
> observations, but this requires a bit of describing my setup as well, 
> so bear with me.
Hm, I still think it can be a reason :-)
> Having skipped ccd, and just working on disks on the first UDA-50, the 
> system seems to not have any problems. But when I do disk operations 
> on the second UDA-50, sooner or later, the process gets stuck in 
> biowait, and never recovers.
It may be a ring buffer sync error, or so.  Since it only occurs on the 
second controller it is likely a software bug somewhere.
I do not think it is a hardware error.
> But for now, this really smells as if we have some kind of issue with 
> additional Unibuses in NetBSD. Interesting detail is that looking at 
> vmsstat -i, I can see that uba0 have generated some interrupts, but 
> uba1 never generate any interrupts.
Interrupt count for the adapters themselves should only be counted in 
case of error, see uba_dw780int_common().
Otherwise interrupts are counted against the device.

> Ragge, what interrupts would the Unibus adapter generate, and does it 
> make sense that only one of the adapters are generating interrupts?
No, if only one adapter would interrupt then the second disk controller 
wouldn't work at all.

It may be a problem with having a secondary unibus adapter.  Would it be 
possible to move the UDA50 to the first unibus (for testing purposes)?
If that works then we have an idea about where to search for the bug at 
least :-)

...and yes, using BDPs should probably help up performance.

-- Ragge