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Date: Thu, 5 Oct 2006 06:09:39 -0400
From: Erik Winkler <ewinkler@...ls.com>
To: john-users@...ts.openwall.com
Subject: Re: JTR and os X macintel


On Oct 4, 2006, at 9:44 PM, Solar Designer wrote:

>
>>  Now, I have compiled the same source with the command :
>> "make macosx-x86-sse2"
>> now test return me :
>>
>> Benchmarking: Traditional DES [128/128 BS SSE2]... DONE
>> Many salts:     1841K c/s real, 1845K c/s virtual
>> Only one salt:  1532K c/s real, 1535K c/s virtual
>
> That's really good performance - it looks like we have a new leader at
> DES-based crypt(3).

It appears this is a 2.16 Ghz core2 duo Intel CPU.  Thanks for the  
insite websiteaccess.


>
>> My mac has a "core duo", is JTR use 2 cores at the same time ?
>
> No.  As discussed on this mailing list oh-so-many times, you need to
> start two instances of JtR manually in order to have it use both CPU
> cores.  For "incremental" mode, a reasonable way to split the task
> across two cores is to set one instance to try lengths 0 through 7 and
> the other to length 8.  The following FAQ entry is relevant:
>
> Q: Does John support multi-processing or distributed processing?
> A: There's no real MP or distributed processing support in John right
> now, but you can distribute the work between a few nodes manually.   
> One
> approach would be to have your nodes (CPUs, machines) each try  
> different
> password lengths.  This is easily accomplished with "incremental"  
> mode's
> "MinLen" and "MaxLen" settings (see CONFIG).  Typically, you would not
> really need to split the work for "single crack" and wordlist modes
> since these are relatively quick, although you may dedicate one  
> node to
> those initially.  You may safely run multiple instances of John in the
> same working directory, all writing to the same "pot file" (this is a
> feature).  You do, however, need to assign each of them a unique  
> session
> name, with "--session".  Other approaches, such as splitting password
> files naively (without regard to salts), are typically less efficient
> (in some cases to the extent where there's no speedup from using
> multiple processors at all).

Actually from a CPU usage screen shot I received from websiteaccess,  
MacOSX seems to have about 80% of one core and 50% of the 2nd core in  
use while running John.  The MacOSX equivalent of "top" shows 99%  
usage by john the ripper alone at the same time.   MacOSX may be  
distributing the load across both processors or even SSE2 units, but  
I am not certain.  It could explain the high benchmarks though.

An interesting test would be benchmarks on a new dual xeon Mac Pro.   
Any graphics designers out there with these new machines?

Erik

>
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> Alexander Peslyak <solar at openwall.com>
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