gmane.comp.lang.smalltalk.squeak.beginners

headers squeak414 | 3 May 21:50

Quoting johnps11 <at> bigpond.com:

> Hi Stan!
>
> Have you tried using the -mmap option when starting Squeak?  I notice that
> according to the squeakvm man page:
>
>   squeak uses a dynamic heap by default with the maximum size  set  to
>   75%  of the available virtual memory or 1 gigabyte, whichever is smaller.
>
> Perhaps Windows doesn't have this limit.  Is one instance of Object bigger
> than 200 bytes? If so you'd expect it to oom.
>
> Assuming you have 2 gig of virtual memory, try starting the VM with
>
> -mmap  1500m
>
> as an option and see if it goes further.
>
> Note you can temporarily increase your virtual memory by running (as root):
>
> dd if=/dev/zero of=/tmp/swapfile bs=1024 count=1M
> mkswap /tmp/swapfile
> swapon /tmp/swapfile
>
> This will increase your VM by 1 Gigabyte - note that on an intel machine
> your VM is usually restricted to a max of about 2gig (unless you start the
> kernel with the right options, and you have a large memory machine, and
> you have a kernel built to support over 4gig of memory).  I'm also
> assuming you have a spare gig of space in /tmp . This lasts till you
> reboot or until you run
>
>      swapoff /tmp/swapfile
>
> as root.
>
> You'll also want to rm that file when you've finished!
>
> I guess that the *nix ports have this restriction for the squeak VM
> because of the assumption that apps should play nice and not suck the
> system into oblivion!
>
> It might also be instructive to run
>
>      vmstat 10 20
>
> in another terminal while you allocate your insanely large array.  You'll
> be able to see if the "freeze" is simply massive disk usage as linux goes
> crazy seeking inside the swapfile - you are allocating 100 million
> references before you even start to allocate Objects! Read the man page on
> vmstat on how to interpret it if you don't know the command.
>
> I hope this helps, and doesn't just confuse...
>
> John
>

> http://lists.squeakfoundation.org/mailman/listinfo/beginners
>

Hi John, not confusing- an excellent response, thanks.

With the memory option it also cruises on under Linux, until it freezes at 70
million objects.

While it's still loading vmstat shows:

procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 2  0  32528  38552  22792 758560    0    0   183   520  295 2399 66  9 17  7
 3  0  32528  38420  22800 758568    0    0     0     3  254 1779 92  8  0  0
 4  0  32528  38420  22804 758568    0    0     0     6  234 2100 93  7  0  0
 4  0  32528  38420  22804 758568    0    0     0     0  239 2125 93  7  0  0
 2  0  32528  38420  22808 758568    0    0     0     0  233 1379 95  5  0  0
 2  0  32528  38420  22816 758568    0    0     0     1  251 2255 92  8  0  0
 2  0  32528  38296  22824 758568    0    0     0     3  244 1963 94  6  0  0
 4  0  32528  38296  22824 758568    0    0     0     0  230 1863 93  7  0  0
 5  0  32528  38296  22832 758568    0    0     0     4  234 2108 91  9  0  0
 2  0  32528  38296  22840 758568    0    0     0    12  228 1616 94  6  0  0
 4  0  32528  38296  22840 758568    0    0     0     0  234 2142 93  7  0  0
 2  0  32528  36608  22680 751824    0    0     0     1  228 1639 94  6  0  0
 1  0  32528  36608  22680 751824    0    0     0     7  234 2128 92  8  0  0
 3  0  32528  36484  22680 751824    0    0     0     3  248 2170 92  9  0  0
 2  0  32528  39080  22560 749472    0    0     2     4  231 1610 93  7  0  0
 4  0  32528  35104  22560 749584    0    0     0     0  239 2137 89 11  0  0
 3  0  32528  34636  22560 749584    0    0     0     0  236 2084 92  8  0  0
 3  0  32528  34960  22568 749584    0    0     0     4  233 1898 93  7  0  0
 4  0  32528  38956  22568 749584    0    0     0     1  238 2277 90 10  0  0
 2  0  32528  36724  22568 749584    0    0     0     0  227 1719 94  6  0  0

Without the -mmap option, once the image has frozen, vmstat shows:

 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 1  0  32528  41884  23220 703504    0    0   130   370  272 2402 74  9 12  5
 1  0  32528  41624  23228 703512    0    0     0     4  215 1094 97  3  0  0
 1  0  32528  41628  23228 703512    0    0     0     0  186  703 98  2  0  0
 1  0  32528  41628  23228 703512    0    0     0     0  179  667 97  3  0  0
 1  0  32528  41628  23236 703512    0    0     0     6  180  668 97  3  0  0
 1  0  32528  41628  23244 703512    0    0     0     4  180  667 97  3  0  0
 1  0  32528  41628  23244 703512    0    0     0     0  179  667 98  2  0  0
 1  0  32528  41628  23244 703512    0    0     0     0  204  765 96  4  0  0
 1  0  32528  41628  23244 703512    0    0     0     2  205 1019 97  3  0  0
 1  0  32528  41628  23260 703516    0    0     0     6  180  665 97  3  0  0
 1  0  32528  41628  23268 703516    0    0     0     1  179  658 98  2  0  0
 1  0  32528  41628  23276 703520    0    0     0     6  180  657 97  3  0  0
 1  0  32528  41628  23276 703520    0    0     0     3  180  655 97  3  0  0
 1  0  32528  41628  23276 703520    0    0     0     0  180  654 97  3  0  0
 1  0  32528  41628  23280 703520    0    0     0     0  179  656 97  3  0  0
 1  0  32528  41628  23280 703520    0    0     0     0  179  659 98  3  0  0
 1  0  32528  41628  23288 703520    0    0     0     1  179  653 97  3  0  0
 1  0  32528  41628  23288 703520    0    0     0     0  179  654 98  2  0  0
 1  0  32528  41628  23288 703520    0    0     0     0  179  654 98  2  0  0
 1  0  32528  41628  23296 703520    0    0     0     3  180  658 98  2  0  0.

Nothing obviously different to me.

At least I can work around this as long as I keep sizes moderate.

Thanks again,   Stan

Re: Linux locks up when handling large data sets