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Re: change to gcc from lcc


On Thu, Nov 20, 2008 at 9:28 PM, Alexey Salmin <alexey.salmin@gmail.com> wrote:
> 2008/11/20 Michael Matz <matz@suse.de>:
>> Hi,
>>
>> On Wed, 19 Nov 2008, H.J. Lu wrote:
>>
>>> On Wed, Nov 19, 2008 at 7:18 PM, Nicholas Nethercote
>>> <njn@csse.unimelb.edu.au> wrote:
>>> > On Tue, 18 Nov 2008, H.J. Lu wrote:
>>> >
>>> >>> I used malloc to create my arrays instead of creating the in the stack.
>>> >>> My program is working now but it is very slow.
>>> >>>
>>> >>> I use two-dimensional arrays. The way I access element (i,j) is:
>>> >>> array_name[i*row_length+j]
>>> >>>
>>> >>> The server that I use has 16GB ram. The ulimit -a command gives the
>>> >>> following output:
>>> >>> time(seconds)        unlimited
>>> >>> file(blocks)         unlimited
>>> >>> data(kbytes)         unlimited
>>> >>> stack(kbytes)        8192
>>> >>
>>> >> ^^^^^^^^^^^^^^^^^^^^^^^^
>>> >>
>>> >> That limits stack to 8MB. Please change it to 1GB.
>>> >
>>> > Why?
>>> >
>>>
>>> int buffer1[250][1000000];
>>>
>>> takes close to 1GB on stack.
>>
>> Read the lines you quoted carefully again.
>>
>>
>> Ciao,
>> Michael.
>>
>
> Can you please talk in a more understandable way? I also think that 4
> * 250 * 1000000 is close to 1073741824 which is 1 Gb. And automatic
> variables are allocated in stack (which is 8Mb here) instead of data
> segment.
>


Here, let me help:

"
>> >>> I used malloc to create my arrays instead of creating the in the stack.
>> >>> My program is working now but it is very slow."

Do you see why he told HJ to reread the lines he quoted?


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