[CoLoCo] How do I make a program fully utilize my dual-core processor?

Ringo 2600denver at gmail.com
Sat Oct 3 23:51:37 BST 2009


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Thanks for all of the great responses! Looks like for now I'll be
sticking to just one core for cracking. Recovering this password
unfortunately isn't enough of a justification for me to go in and hack
the source.

Ringo

NICK VERBECK wrote:
> If you wrote the program yourself or have access to the source. You
> could extend it to use Threads. However with threads you can truly
> only fire-up as many threads as you have cores. Each thread will use a
> separate core to run in, but once you get 2 threads in the same core
> you will start context switching between each thread in that core
> slowing down the actual speed of those 2 threads.
> 
> On Sat, Oct 3, 2009 at 8:31 AM, Neal McBurnett <neal at bcn.boulder.co.us> wrote:
>> In general, the problem you identify is one of the most daunting
>> issues facing computer science.  It is getting much harder to speed up
>> individual processors, so the way to give people more power is to give
>> them more cores.  But we often can't find a suitable way to take
>> advantage of them to solve a given problem....
>>
>>  http://en.wikipedia.org/wiki/Parallel_computing
>>
>> It all depends on exactly what you want to do.  You are in luck
>> because recovering a password is easily done in parallel, as James
>> notes.  But many other interesting tasks can't be easily parallelized.
>>
>> Neal McBurnett                 http://neal.mcburnett.org/
>>
>> On Sat, Oct 03, 2009 at 07:35:00AM -0600, James Wyatt wrote:
>>> Assuming both instances can work on different hashes you could run your
>>> app twice and assign processor affinity to each process.
>>>
>>> http://www.linuxjournal.com/article/6799
>>>
>>>
>>> You could do something with erlang if you wanted to do it with style,
>>> but that would certainly be overkill.
>>>
>>> Jim
>>>
>>>
>>>
>>> On Sat, Oct 3, 2009 at 1:31 AM, Ringo <2600denver at gmail.com> wrote:
>>>
> Hey Ubuntu experts,
> 
> I've got an intel dual-core processor which Ubuntu (intrepid) runs great
> on. It will fully utilize both cores if I've got lots of programs
> running but each program is confined to only one core.
> 
> I've looked around online to find out how to make a program use both
> cores, but I can't find any advice on this outside of the convoluted
> process of running a program inside a virtual machine. I'm trying to
> recover a password from a hash and one core is at 100% while the other
> is around 3% usage.
> 
> Any ideas?
> 
> Thanks,
> Ringo
> 
>>>
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