Re: NetBSD hardclock overhead growth

["Michael L. Hitch" <mhitch%NetBSD.org@localhost>]

On Mon, 24 Aug 2015, John Klos wrote:

> I have the 1.3 ROM. There are two obvious possibilities:
>
> The 1.2 ROM initializes the cache tags properly. This doesn't seem likely 
> because the notes which talked about the upgrade from 1.2 to 1.3 didn't 
> mention anything about the cache.
>
> Or... my cache has a defective page (or two, or three) whereas yours does 
> not, so my machine's cache doesn't get enabled because the code is meant for 
> the KA660 and doesn't take in to account bad pages.
>
> I'll have to do some tests to see if I can get my cache enabled. Yay!

  I've added some test to get some of the information from the registers.

VAXstation 4000 VLC
ka48: CCR = 0x10, BWF0=0x420000d0, BEHR=0x000000ff
total memory = 24188 KB
avail memory = 19228 KB
--
VAXstation 4000 VLC
ka48: CCR = 0x10, BWF0=0x420000d0, BEHR=0x02e000ff
ka48: BWF0=0x430001d1
total memory = 24188 KB
avail memory = 19224 KB
--
VAXstation 4000 VLC
ka48: CCR = 0x10, BWF0=0x420000d0, BEHR=0x000000f7
ka48: BWF0=0x430001d1
total memory = 24188 KB
avail memory = 19224 KB

  The first two were from one of my VLC systems and shows that it has all 
8 banks of cache.  The second one was from another VLC and looks like one 
bank is missing on that.  A third VLC I wasn't able to boot from to look 
at.

  You can see that I was able to read the BEHR register on my systems, so 
I'm also not sure why John was getting a panic trying to read it.

Mike

---
Michael L. Hitch                        mhitch%montana.edu@localhost
Operations Consulting,  Information Technology Center
Montana State University, Bozeman, MT     USA