[HECnet] KLH10 not idling host CPU

[Mark Pizzolato]

Hi Al,

On Sunday, March 4, 2018 at 8:18 PM, Alastair Boyanich wrote:
> sim> SHOW VERSION
> VAX simulator V3.9-0 [64b data, 64b addresses, Ethernet support]
> sim>
> 
> Running on NetBSD 7.1.1 Rpi2 or 8.4 on AXP

The output of SHOW VERSION using the github codebase will help explain 
more about why or why not idling may not be working on your host system.

The current code will make a best effort to achieve idling, but it may not be
possible depending on capabilities of the host platform.   Idling needs clock 
ticks and minimum sleep times on the host platform to be less than 10ms 
in order to provide VAX system idling.  This is necessary since the simulated 
VAX systems have 10ms ticks which have no chance of being reasonably 
delivered if the host doesn't support short duration sleeps and granularity 
of host system time keeping less than 10ms as well.  Your NetBSD kernel 
may have a relatively large clock tick.  The kernel could be built with a small 
enough clock tick and then idling would work.  SHOW VERSION will display
details to understand this:

sim> show version
MicroVAX 3900 simulator V4.0-0 Beta
    Simulator Framework Capabilities:
        64b data
        64b addresses
        Threaded Ethernet Packet transports:PCAP:TAP:VDE: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 5.4.0 20160609
        Simulator Compiled as C arch: x64 (Release Build) on Mar  4 2018 at 21:14:41
        Memory Access: Little Endian
        Memory Pointer Size: 64 bits
        Large File (>2GB) support
        SDL Video support: SDL Version 2.0.4
        PCRE RegEx support for EXPECT commands
        OS clock resolution: 1ms
        Time taken by msleep(1): 1ms
        OS: Linux mark-VirtualBox 4.4.0-112-generic #135-Ubuntu SMP Fri Jan 19 11:48:36 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
        git commit id: f6e806df

> I'll grab the latest master and check it out. I've been curious to see if the
> graphical console fb stuff from 9track.net or the vax-mp made it into the
> mainline.

The MicroVAX I, MicroVAX II and MicroVAX 3900 will be built with support 
for a QVSS is the host build environment has libSDL2 available.

The vax-mp stuff twisted around the core simulator framework too much 
to end up getting merged. 

- Mark