[Vm-dev] We need help from VM experts. Re: Freeze after Morph Activity

David T. Lewis lewis at mail.msen.com
Sun Feb 5 20:42:49 UTC 2017


On Sun, Feb 05, 2017 at 04:09:39PM -0300, Juan Vuletich wrote:
>  
> Hi Folks,
> 
> It seems we found a problem in Spur-64 on Linux. Eliot & VM developers 
> and experts, please, we need your help.
> 
> Cuis users have been experiencing this problem since we started using 
> Spur-64. At random times, the image just stops working. No Smalltalk 
> process is run, and the VM needs to be killed from the OS.
> 
> In my experience, most of the time it takes several hours for the 
> problem to happen. Dan found a simple way to make it happen rather 
> quickly. No FFI is involved, just pretty basic Smalltalk. I can confirm 
> that the problem does not happen using Spur-32 on the same platform.
> 


I can confirm this on my Ubuntu laptop running Cuis5.0-3040-spur-64.image.

I filed in the Tokenish.st demo, and started several Tokenish morphs that
bounced along cheerfully until the image hung up.

The VM is still running and using CPU. Top shows about 5% CPU, which several
times greater than for an idle image, but certainly not abnormally high.

The actual VM process shows a "waiting" state in /proc/<pid>/status, which
is exactly like what I would expect for a normal running VM. Here is a sample
of what I see for the hung image/VM:

  lewis at lewis-Gazelle-Pro:/proc/32609$ cat /proc/32609/status
  Name:	squeak
  State:	S (sleeping)
  Tgid:	32609
  Ngid:	0
  Pid:	32609
  PPid:	2779
  TracerPid:	0
  Uid:	1000	1000	1000	1000
  Gid:	1000	1000	1000	1000
  FDSize:	256
  Groups:	4 24 27 30 46 115 131 1000 
  VmPeak:	  147456 kB
  VmSize:	  131156 kB
  VmLck:	       0 kB
  VmPin:	       0 kB
  VmHWM:	   40468 kB
  VmRSS:	   40464 kB
  VmData:	   57496 kB
  VmStk:	    1740 kB
  VmExe:	    1304 kB
  VmLib:	    5916 kB
  VmPTE:	     240 kB
  VmSwap:	       0 kB
  Threads:	2
  SigQ:	0/31381
  SigPnd:	0000000000000000
  ShdPnd:	0000000000000000
  SigBlk:	0000000000000000
  SigIgn:	0000000000001000
  SigCgt:	0000000190000648
  CapInh:	0000000000000000
  CapPrm:	0000000000000000
  CapEff:	0000000000000000
  CapBnd:	0000003fffffffff
  Seccomp:	0
  Cpus_allowed:	ff
  Cpus_allowed_list:	0-7
  Mems_allowed:	00000000,00000001
  Mems_allowed_list:	0
  voluntary_ctxt_switches:	14946247
  nonvoluntary_ctxt_switches:	2443
  lewis at lewis-Gazelle-Pro:/proc/32609$ 

The VM that I am using is:

  Virtual Machine
  ---------------
  /usr/local/lib/squeak/5.0-201608171728-64/squeak
  Croquet Closure Cog[Spur] VM [CoInterpreterPrimitives VMMaker.oscog-cb.1919]
  Unix built on Sep 25 2016 15:59:10 Compiler: 4.6.3
  platform sources revision VM: 201608171728 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $ Date: Wed Aug 17 10:28:01 2016 -0700 $ Plugins: 201608171728 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $
  CoInterpreter VMMaker.oscog-cb.1919 uuid: 00a8dd2a-bc8d-4552-b400-be781c8aabec Sep 25 2016
  StackToRegisterMappingCogit VMMaker.oscog-cb.1919 uuid: 00a8dd2a-bc8d-4552-b400-be781c8aabec Sep 25 2016


I cannot see what is wrong, but maybe this will prompt some ideas.

Dave



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