[Simh] Ultrix network issues

[Mark Pizzolato]

On Thursday, November 15, 2018 at 3:27 PM, Douglas Hall wrote:
> On Thu, 15 Nov 2018, at 17:25, Mark Pizzolato wrote:
> 
> > From what you've said here, not being a Xen user myself, it is not
> > 100% clear exactly what's running where.
> >
> > Is it: Ultrix on simh running on Debian Stretch running under Xen?
> > OR:  Ultrix on simh running on Xen running under Debian Stretch?
> > OR: Something else...?
> 
> Sorry if that wasn't clear.  I have a Xen environment running with Debian
> Stretch in Dom0 and also in the DomU that has simh running.
> 
> >
> > Without regard to that, if you:
> > 1) Stop the VMS instance running under your configuration
> > 2) Stop the Ultrix instance running under your configuration
> > 3) Change the Ultrix's configuration file to attach the VMS instance's
> > boot disk image
> > 4) Start simh with the otherwise unchanged Ultrix configuration
> > 5) Confirm that networking with the VMS OS running in the simh Ultrix
> > simulator is absolutely normal or if it exhibits issues similar to the
> > Ultrix OS's behavior.
> 
> No change. network performance with VMS is as expected, performance with
> Ultrix is unusable.  I can attach a pcap of a file transfer to the Ultrix system if it
> helps.
> 
> As a further test, I installed NetBSD8/vax in simh on the same DomU I have
> Ultrix on and it doesn't exhibit any unusual issues with network performance.
> 
> For reference, here is the  show version
> 
> MicroVAX 3900 simulator V4.0-0 Current
>     Simulator Framework Capabilities:
>         64b data
>         64b addresses
>         Threaded Ethernet Packet transports:PCAP:TAP:NAT:UDP
>         Idle/Throttling support is available
>         Virtual Hard Disk (VHD) support
>         RAW disk and CD/DVD ROM support
>         Asynchronous I/O support (Lock free asynchronous event queue)
>         Asynchronous Clock support
>         FrontPanel API Version 12
>     Host Platform:
>         Compiler: GCC 4.2.1 Compatible Clang 3.8.1 (tags/RELEASE_381/final)
>         Simulator Compiled as C arch: x64 (Release Build) on Nov 10 2018 at
> 16:37:50
>         Memory Access: Little Endian
>         Memory Pointer Size: 64 bits
>         Large File (>2GB) support
>         SDL Video support: No Video Support
>         RegEx support for EXPECT commands
>         OS clock resolution: 1ms
>         Time taken by msleep(1): 1ms
>         OS: Linux ermine-xen 4.9.0-8-amd64 #1 SMP Debian 4.9.130-2 (2018-10-
> 27) x86_64 GNU/Linux
>         git commit id: acbea915
>         git commit time: 2018-11-10T04:34:43-0800

Thanks for the SHOW VERSION output.

Meanwhile the more important detail will be things like SHOW ETHERNET
And SHOW XQ STATS, and just SHOW XQ (after the OS has exhibited the 
problem AND after a different OS doesn't exhibit the problem.

In your configuration file for BOTH the working and the non-working cases
please try variations of:

      SET XQ TYPE=DEQNA
      SET XQ TYPE=DELQA
      SET XQ TYPE=DELQA-T

This change would occur in your configuration file before you attach the 
device.

If you still get everything but Ultrix working for each of these cases, then
the only difference is the potential timing regarding how the Ultrix driver
handles the buffer descriptor lists vs how the other operating systems do 
it.

Let me know what you find.

- Mark