john-users - Re: JtR OMP Questions

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Date: Mon, 4 Jun 2012 17:37:59 -0700 (PDT)
From: NeonFlash <psykosonik_frequenz@...oo.com>
To: "john-users@...ts.openwall.com" <john-users@...ts.openwall.com>
Subject: Re: JtR OMP Questions

Thanks. I knew about the option, OMP_NUM_THREADS which can be passed at command line to configure the number of threads to be used. However, this works only on the Linux Platform. Is there a similar option available for the Windows version of JtR as well? Or is it hardcoded and needs to be recompiled for a different value of OMP_NUM_THREADS.

I wanted to know if it is possible to do this on Windows Version. That would be really helpful.

I will check the option, GOMP_SPINCOUNT and also see what it means :)

Thanks.

________________________________
 From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com 
Sent: Monday, June 4, 2012 10:15 PM
Subject: Re: [john-users] JtR OMP Questions

On Mon, Jun 04, 2012 at 09:48:12PM +0530, SAYANTAN DATTA wrote:
> eg.
> bash$ OMP_NUM_THREAD=3 ./john -te -fo=raw-md5
> it will use only 3 threads.

...except that there's no OpenMP support for raw-md5 currently, so it
will only use 1 thread regardless of OMP_NUM_THREADS.  Oh, and
OMP_NUM_THREAD was a typo (should be OMP_NUM_THREADS).  A better example
would be:

OMP_NUM_THREADS=3 ./john -te=1 -fo=des

Also, GOMP_SPINCOUNT may need to be tuned on a particular system.
I recommend testing these values: 10000, 100000, 300000 (gcc 4.6.0+
default), 3000000, 10000000.  No need to fine-tune it, so testing these
5 values should be enough.

Alexander