[Simh] DECwindows issues
Hans Hübner
hans.huebner at gmail.com
Tue Jul 24 01:59:27 EDT 2018
Thank you for the explanation, Mark.
I've added the line "kern.hz=1000" to the file /boot.loader.conf and
rebooted. Now the system behaves much better and the issue went away.
-Hans
2018-07-24 6:27 GMT+02:00 Mark Pizzolato <Mark at infocomm.com>:
> Hi Hans,
>
>
>
> Notice: “Time taken by msleep(1): 20ms”
>
>
>
> Well, the simulator framework implements idling with sleeps. Meanwhile
> the simulated VAX has a clock which is architecturally defined to tick at
> 10ms intervals. If any call to sleep for 1 millisecond actually sleeps for
> 20 milliseconds, then whenever the system idles the clock is going to get
> far behind. Older simh versions would simply refuse to idle when the sleep
> granularity was too large. The current implementation tries to actually
> allow idling when the host system’s sleep is large and also tries hard to
> schedule catchup clock ticks so that simulated time tracks pretty closely
> with wall clock time.
>
>
>
> This attempt to run with catchup clock ticks, hasn’t been extensively
> tested since only a few BSD systems actually have large scheduling clock
> ticks built into the kernel by default. Therefore, there may be problems.
> Most other systems (Windows, Linux, and OS X) have host system clock ticks
> on the order of 1-2ms so these systems don’t have this problem.
>
> You can build a kernel for your BSD system by specifying or changing the
> value of HZ somewhere in the kernel configuration information, or you could
> try running on a different host platform.
>
>
>
> - Mark
>
> *From:* Hans Hübner [mailto:hans.huebner at gmail.com]
> *Sent:* Friday, July 20, 2018 10:57 PM
> *To:* Mark Pizzolato <Mark at infocomm.com>
> *Cc:* Matt Burke <matt at 9track.net>; Simh <simh at trailing-edge.com>
> *Subject:* Re: [Simh] DECwindows issues
>
>
>
> Hi Matt,
>
>
>
> 2018-07-20 20:26 GMT-04:00 Mark Pizzolato <Mark at infocomm.com>:
>
> On Friday, July 20, 2018 3:45 PM, Hans Hübner wrote:
> > 2018-07-20 18:28 GMT-04:00 Matt Burke <matt at 9track.net>:
> > > On 19/07/2018 06:41, Hans Hübner wrote:
> > > > I see either one of the DECwindows processes (window or session
> > > > manager) use more than 50% of the VAX CPU or, if I kill both
> > > > processes, the emulator taking up 100% of its host CPU with no VAX
> > > > process showing up in MONITOR PROC/TOPCPU. The emulated system is
> too
> > > > slow to be used, effectively.
> > >
> > > I don't seem to be able to reproduce this (on Debian 9.5).
> >
> > I'm running SIMH on FreeBSD, but I can switch if the problem is related
> to that.
>
> It might be related to the host OS.
>
> Please let it get to the state you're complaining about and then:
> ^E
> sim> SHOW VERSION
> sim> CLOCK
> sim> SHOW CPU
>
> and send the output produced back here.
>
>
>
> Here you go:
>
>
>
> sim> show version
>
> 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
>
> Asynchronous I/O support (Lock free asynchronous event queue)
>
> Asynchronous Clock support
>
> FrontPanel API Version 12
>
> Host Platform:
>
> Compiler: GCC 6.4.0
>
> Simulator Compiled as C arch: x64 (Release Build) on Jul 18 2018
> at 07:32:15
>
> Memory Access: Little Endian
>
> Memory Pointer Size: 64 bits
>
> Large File (>2GB) support
>
> SDL Video support: SDL Version 2.0.7
>
> PCRE RegEx (Version 8.42 2018-03-20) support for EXPECT commands
>
> OS clock resolution: 1ms
>
> Time taken by msleep(1): 20ms
>
> OS: FreeBSD vaxhost 11.2-RELEASE FreeBSD 11.2-RELEASE #0 r335510:
> Fri Jun 22 04:32:14 UTC 2018 root at releng2.nyi.freebsd.org:
> /usr/obj/usr/src/sys/GENERIC amd64
>
> git commit id: 15fd71b9
>
> git commit time: 2018-07-17T22:05:05-0700
>
> sim> show clock
>
> Minimum Host Sleep Time: 20 ms (50Hz)
>
> Host Clock Resolution: 1 ms
>
> Execution Rate: 1,358,783,530 cycles/sec
>
> Idling: Enabled
>
> Time before Idling starts: 20 seconds
>
> Calibrated Timer: Internal Timer
>
> Catchup Ticks: Enabled for clocks ticking faster than 50 Hz
>
> Calibration: Always
>
>
>
> VAXStation 3900 (KA655) clock device is CLK
>
> Calibrated Timer 0:
>
> Running at: 100 Hz
>
> Tick Size: 10 msecs
>
> Ticks in current second: 82
>
> Seconds Running: 80 (1:20 minutes)
>
> Real Time: 3144059812
>
> Virtual Time: 3144059812
>
> Next Interval: 1,000
>
> Base Tick Delay: 5,000
>
> Initial Insts Per Tick: 5,000
>
> Current Insts Per Tick: 13,587,835
>
> Initializations: 5
>
> Ticks: 6,795
>
> Total Ticks: 8,082
>
> Peak Clock Skew: 825.867 msecs slow
>
> Ticks Acked: 6,795
>
> Tick Time: 1:07.95 minutes
>
> Total Tick Time: 1:20.81 minutes
>
> Catchup Ticks Sched: 6,065
>
> Initialize Base Time: 07:53:37.188
>
> Tick Start Time: 07:53:37.196
>
> Wall Clock Time Now: 07:55:35.790
>
> Catchup Tick Time: 07:54:56.606
>
> Catchup Base Time: 07:53:48.656
>
> Total Time Idled: 2.439 seconds
>
> VAXStation 3900 (KA655) clock device is Internal Calibrated
> Timer(INT-TIMER)
>
> Calibrated Timer 8:
>
> Running at: 10 Hz
>
> Tick Size: 100 msecs
>
> Ticks in current second: 6
>
> Seconds Running: 23 (23 seconds)
>
> Calibration Opportunities: 23
>
> Instruction Time: 1570864774
>
> Real Time: 3144081177
>
> Virtual Time: 3144082804
>
> Next Interval: 1,500
>
> Base Tick Delay: 90,585,569
>
> Initial Insts Per Tick: 50,000
>
> Current Insts Per Tick: 135,878,353
>
> Initializations: 3
>
> Ticks: 235
>
> Tick Time: 23.5 seconds
>
> Initialize Base Time: 07:53:37.180
>
> Tick Start Time: 07:53:37.180
>
> Wall Clock Time Now: 07:55:35.790
>
> sim> show cpu
>
> CPU idle=VMS, idle enabled, model=MicroVAX 3900 (KA655), NOAUTOBOOT
>
> 64MB, HALT to SIMH
>
>
>
> Thanks!
> Hans
>
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