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Date: Wed, 05 Dec 2012 01:40:40 +0100
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: Re: self-test duration vs. GPU benchmarks

On 07/17/2012 07:44 PM, Solar Designer wrote:
> When testing GPU formats, especially for slow hashes, the self-test is
> often taking multiple seconds, and it affects the c/s rate reported
> while cracking.
>
> The attached patch corrects this to some extent by only running the
> self-test exactly once for each format (previously, it'd be run twice
> for one vs. many salts benchmarks, and also before the start of each
> cracking mode when running in "batch mode") and by not including its
> duration in total session time.
>
> These changes will appear in core and thus in bleeding.

As core John development has come to a full halt I have now merged this 
patch to unstable-jumbo instead of just to bleeding. We'll want it in 
Jumbo-8 anyway.

> Unfortunately, there may be some bugs that would be caught by the
> repeated self-tests, but would not be caught now.  There were some in
> the past.  So we'll need to be trying -DDEBUG builds on some occasions.
> I also intend to improve the self-tests to make them faster yet less
> likely to miss issues like that.  But it's a separate task, for later.

I would like to add a new format flag in Jumbo: FMT_GPU. With that in 
place, we can omit GPU formats from the --test [all] case (with a 
comment printed) right now, and we could also handle self-tests somewhat 
differently from CPU formats - like testing a good number of hashes in 
one call to crypt_all() instead of trying one at a time in a large 
number of long-duration calls.

magnum

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