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Cog using virtual memory under Linux

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Herbert König

Cog using virtual memory under Linux

Hi,

I run a Squeak image under Cog on a hosted virtual Linux server.
Croquet Closure Cog VM [CoInterpreter VMMaker.oscog-eem.201]
Unix built on Aug 14 2012 09:25:00 Compiler: 4.1.2 20080704 (Red Hat
4.1.2-48)
platform sources revision VM: r2585

Lately I used it for some optimizations running for several days and the
Hoster complained that I create too much IO, my CPU usage being no
problem. I have no idea how I could create IO but it occurs during my
CPU usage. I do no IO I know of. Only idea I have is accessing virtual
memory. Changes file is 37MB and not growing during the computations.

TOP tells me the image is actually using 60 MB but virtual memory is
1GB. VM statistics reports 50 MB, 40 MB used. The virtual server has 512
MB, 200MB free. Nothing else runs on the machine. The server has no X
running I operate Squeak through Tight VNC tunnelled through SSH.

Is it possible that Cog frequently tries to access virtual memory under
these circumstances? The system does not slow down compared to the same
calculations on my Windows laptop where I have sufficient memory.

Any ideas of other ways I might involuntarily create the IO load?

Thanks,

Herbert

Levente Uzonyi-2

Re: Cog using virtual memory under Linux

On Thu, 6 Mar 2014, Herbert König wrote:

> Hi,
>
> I run a Squeak image under Cog on a hosted virtual Linux server.
> Croquet Closure Cog VM [CoInterpreter VMMaker.oscog-eem.201]
> Unix built on Aug 14 2012 09:25:00 Compiler: 4.1.2 20080704 (Red Hat
> 4.1.2-48)
> platform sources revision VM: r2585
>
> Lately I used it for some optimizations running for several days and the
> Hoster complained that I create too much IO, my CPU usage being no problem. I
> have no idea how I could create IO but it occurs during my CPU usage. I do no
> IO I know of. Only idea I have is accessing virtual memory. Changes file is
> 37MB and not growing during the computations.
>
> TOP tells me the image is actually using 60 MB but virtual memory is 1GB. VM
> statistics reports 50 MB, 40 MB used. The virtual server has 512 MB, 200MB
> free. Nothing else runs on the machine. The server has no X running I operate
> Squeak through Tight VNC tunnelled through SSH.
>
> Is it possible that Cog frequently tries to access virtual memory under these
> circumstances? The system does not slow down compared to the same
> calculations on my Windows laptop where I have sufficient memory.
>
> Any ideas of other ways I might involuntarily create the IO load?

IO usually means disk usage, so I don't think this has anything to do with
Cog or virtual memory. You can use iostat and iotop to see what's using up
IO bandwidth.

Levente

>
> Thanks,
>
> Herbert
>
>

Herbert König

Re: Cog using virtual memory under Linux

Thanks Levente,

I'll look into that.

Cheers,

Herbert

Am 06.03.2014 16:55, schrieb Levente Uzonyi:

On Thu, 6 Mar 2014, Herbert König wrote:

Hi,

I run a Squeak image under Cog on a hosted virtual Linux server.
Croquet Closure Cog VM [CoInterpreter VMMaker.oscog-eem.201]
Unix built on Aug 14 2012 09:25:00 Compiler: 4.1.2 20080704 (Red Hat 4.1.2-48)
platform sources revision VM: r2585

Lately I used it for some optimizations running for several days and the Hoster complained that I create too much IO, my CPU usage being no problem. I have no idea how I could create IO but it occurs during my CPU usage. I do no IO I know of. Only idea I have is accessing virtual memory. Changes file is 37MB and not growing during the computations.

TOP tells me the image is actually using 60 MB but virtual memory is 1GB. VM statistics reports 50 MB, 40 MB used. The virtual server has 512 MB, 200MB free. Nothing else runs on the machine. The server has no X running I operate Squeak through Tight VNC tunnelled through SSH.

Is it possible that Cog frequently tries to access virtual memory under these circumstances? The system does not slow down compared to the same calculations on my Windows laptop where I have sufficient memory.

Any ideas of other ways I might involuntarily create the IO load?

IO usually means disk usage, so I don't think this has anything to do with Cog or virtual memory. You can use iostat and iotop to see what's using up IO bandwidth.

Levente

Thanks,

Herbert