[Simh] VAX Simulator 99.9% CPU , and flush nvram never finishes .

[Mark Pizzolato]

On Wednesday, May 23, 2018 at 4:20 PM, James W. Laferriere wrote:
>  	Hello All ,  I am noticing a VERY High cpu with JUST simh running and it
> does not reduce over time .  Any ideas ?  Hopefully everything needed is below
> .
> 
>  		Tia ,  JimL
> 
> 
> ***	Exiting with this configuration never returns from the below
>  	writing buffer .
> 
> sim> exit
> Goodbye
> NVR: writing buffer to file
> 
> 
> *** the TOP output below is with simh sitting at the sim> prompt no boot has
> been issued .
> 
> top - 15:03:32 up 1 day, 21:10,  2 users,  load average: 0.97, 0.44, 0.20
> Tasks: 107 total,   1 running, 106 sleeping,   0 stopped,   0 zombie
> Cpu(s): 99.7%us,  0.3%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
> Mem:   1012484k total,   935692k used,    76792k free,   175564k buffers
> Swap:  8388604k total,      608k used,  8387996k free,   304496k cached
> 
>    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 14162 vaxuser   20   0  692m  29m 5076 S 99.6  2.9   2:34.66 vaxX
> ...snip...
> 
> 
> sim> sh ver
> VAXStation 3900 (KA655) 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 4.8.2
>          Simulator Compiled as C arch: x64 (Debug Build) on Apr 15 2018 at
> 18:06:09
>          Memory Access: Little Endian
>          Memory Pointer Size: 64 bits
>          Large File (>2GB) support
>          SDL Video support: SDL Version 1.2.15
>          PCRE RegEx (Version 8.39 2016-06-14) support for EXPECT commands
>          OS clock resolution: 1ms
>          Time taken by msleep(1): 1ms
>          OS: Linux ns4 3.10.17 #2 SMP Wed Oct 23 16:34:38 CDT 2013 x86_64 AMD
> Opteron(tm) Processor 6376 AuthenticAMD GNU/Linux
> >>>	on VMWare 6.5
>          git commit id: c8beee2d
>          git commit time: 2018-04-15T12:53:29-07:00

Hi James,

Hmmm...

First, please try the lastest GitHub code.

Second, I see you've built the simulator with video support, but you're not using any Video device in your configuration.  Additionally, I see that you're working with the older SDL version 1 video.  SDL version 1 was needed when video capabilities were first added to simh, but at this point libSDL Version 2 is available on essentially all interesting host platforms, so libSDL1 is deprecated and some changes coming in the near future will remove any attempt to support it.
Try installing the libSDL Version 2 development package and rebuilding the simulator.

Third, unless you're preparing to dig deeply under the covers, you probably want to run the optimized vs debug build of the simulator.

Let us know where this takes you.

- Mark