[Pharo-project] Memory problems on Windows

Jimmie Houchin jlhouchin at gmail.com
Sat Sep 4 04:52:15 CEST 2010


Hello,

Sorry for the delay in reply. For some reason the first time I looked at 
your message in my newsreader (Thunderbird/GMane) the message was in 
French and written to someone else. Apparently the software did 
something strange.

To answer your question. Yes. I tried this in both the standard vm and 
the standard Pharo 1.1 image.

I start the vm/image with -memory: 1000
and open a new Workspace, then copy the below memory settings and doit.
I then do  a := Array new: 100000000.

That seemingly succeeds but only takes me up to a little below 500mb 
ram. If I attempt to do another array of another 100,000,000 objects, I 
get the Low Space error.

With the standard vm and image, it just sits there consuming cpu with 
simply doing the array initialization. I am on a quad core server with 
6gm ram and it has currently consumed over 36 cpu minutes of one of the 
cores. At this point I quit the image. I could do things in the UI but 
it is not very responsive.

In the Cog vm/image, the array creation returns almost immediately and 
waits for other instructions.

As I write this I have to go back to Squeak 3.7.1vm and either the 3.8 
or 3.10 image, for it to be successful. Outside of that I can't get past 
500mb of ram. This server generally sits at only using 30% of ram.

For enterprise/business endeavors, I thing Pharo really needs to be able 
to use all the memory the OS will allow it. I know that it being a 32 
bit app does create some limits on some OSes. But neither of my Vista 
machines imposes a limit that I can't live with at the moment.

Thanks for your reply. I am neither a vm nor Smalltalk expert so I don't 
know how to proceed from here outside of reducing my applications memory 
needs by putting more into the database and only having the data in 
memory that is absolutely necessary for the analysis I am attempting.

Jimmie

On 9/1/2010 4:48 AM, Stéphane Ducasse wrote:
> do you have the same problem with the normal VM?
>
> On Sep 1, 2010, at 5:25 AM, Jimmie Houchin wrote:
>
>> Hello,
>>
>> I am developing an application which processes and generates a large amount of data. In a recent attempt I encountered an Space is Low error.
>>
>> This is occurring in a Pharo 1.1 image using the latest Pharo and Cog VMs. I am opening the vm with the -memory: 1000 parameter.
>> The below code I have applied the from the Squeak list from the 100 Million Objects thread. But the problem occurs at about 500mb of ram on a computer with 3 (or 6) gb of ram, with only 65% of physical ram in use. The os is Vista.
>>
>> Any help in using more memory, as much as necessary for the app, would be greatly appreciated.
>>
>> initializeMemorySettings
>> "Initialize the memory and GC settings to be more in line with QF requirements"
>>
>> "The following settings affect the rate incremental GCs and tenuring"
>>
>> "Limit incremental GC activity to run every 40k allocations"
>>   SmalltalkImage current vmParameterAt: 5 put: 40000. "allocations between GCs (default: 4000)"
>> "Limit tenuring threshold to only tenure w/>  10k survivors"
>>   SmalltalkImage current vmParameterAt: 6 put: 10000. "tenuring threshold (default: 2000)"
>>
>> "These settings affect overall memory usage"
>>
>> "Only give memory back to the OS when we have more than 16MB free"
>>   SmalltalkImage current vmParameterAt: 24 put: 16*1024*1024. "default 8MB"
>> "Try to keep 8MB headroom at all times"
>>   SmalltalkImage current vmParameterAt: 25 put: 8*1024*1024. "default 4MB"
>> "These settings describe what to do when we're close to running out of free space"
>>
>> "Tell the VM that we'd rather grow than spinning in tight GC loops"
>>   SmalltalkImage current gcBiasToGrow: true. "default: false"
>>   "Tell the VM to do a fullGC for good measure if the above growth exceeded 16MB"
>>   SmalltalkImage current gcBiasToGrowLimit: 16*1024*1024. "default: 0"
>>
>> Thanks,
>>
>> Jimmie Houchin
>>
>>
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>> Pharo-project at lists.gforge.inria.fr
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