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

Neal McBurnett neal at bcn.boulder.co.us
Tue Oct 6 23:56:06 BST 2009


http://en.wikipedia.org/wiki/List_of_distributed_computing_projects
http://en.wikipedia.org/wiki/Distributed_computing
-Neal

On Tue, Oct 06, 2009 at 04:46:58PM -0600, Andrew Barney wrote:
> Does the term "distributed workload" refer to multiple computers working in
> unison on the same task?
> 
> Because i would think that if trying to crack passwords that multiple systems
> (perhaps a computer lab) would be the way to go.
> 
> If that's what it means then, i would like to know of any programs that use
> distributed workloads other than cracking software. And even some info on how
> people program code to do that. Is it some sort of P2P software?
> 
> I know awhile back there were some researchers using peoples screensavers to do
> cancer research...
> 
> -Andrew
> 
> On Mon, Oct 5, 2009 at 8:14 PM, Neal McBurnett <neal at bcn.boulder.co.us> wrote:
> 
>     http://pdfcrack.sourceforge.net/faq.html says it can be done:
> 
>     ----
>     Does PDFCrack support distributed and/or multicore/multicpu-systems?
> 
>     Not yet. The project is open for contributions! ;)
>     Distributed workloads can be done by some clever working with the
>     save-files though but I have not tried it.
>     ----
> 
>     I don't know what it means about save-files, but I suggest looking into it.
> 
>     Neal McBurnett                 http://neal.mcburnett.org/
> 
>     On Mon, Oct 05, 2009 at 08:30:35PM -0400, Ringo wrote:
>     > -----BEGIN PGP SIGNED MESSAGE-----
>     > Hash: SHA1
>     >
>     > I'm actually using pdfcrack, so I'm not technically breaking a hash.
>     > Unfortunately, it only seems to do one thread at a time. I suppose I
>     > could have one instance working on an x character password and one
>     > instance working on an x+1 character password but that would require
>     > some monitoring.
>     >
>     > It's the only pdf cracking utlility I've found but if people know of
>     > others I'd be thrilled to try them.
>     >
>     > Ringo
>     >
>     > Ryan Maki wrote:
>     > > Additionally, serious password cracking software might also be able to
>     > > utilize your graphics card, depending on make and model.~Ryan
>     > >
>     > > On Mon, Oct 5, 2009 at 4:30 PM, Neal McBurnett <neal at bcn.boulder.co.us>
>     wrote:
>     > >
>     > >> I'd be surprised if good cracking applications didn't already have an
>     > >> option to do multi-threading to use all your cores. Â What software
>     are
>     > >> you using?
>     > >>
>     > >> -Neal
>     > >>
>     > >> On Sat, Oct 03, 2009 at 06:51:37PM -0400, Ringo wrote:
>     > > 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. Â It is getting much harder to
>     speed up
>     > >>>>>> individual processors, so the way to give people more power is to
>     give
>     > >>>>>> them more cores. Â But we often can't find a suitable way to take
>     > >>>>>> advantage of them to solve a given problem....
>     > >>>>>>
>     > >>>>>> Â http://en.wikipedia.org/wiki/Parallel_computing
>     > >>>>>>
>     > >>>>>> It all depends on exactly what you want to do. Â You are in luck
>     > >>>>>> because recovering a password is easily done in parallel, as James
>     > >>>>>> notes. Â 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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