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Date: Fri, 19 Apr 2013 07:59:42 -0700
From: Tavis Ormandy <taviso@...xchg8b.com>
To: john-dev@...ts.openwall.com
Subject: Re: minor raw-sha1-ng pull request

magnum <john.magnum@...hmail.com> wrote:

> On 19 Apr, 2013, at 6:33 , Tavis Ormandy
> <taviso@...xchg8b.com> wrote:
> > Hey Magnum, I noticed I could pull a bit of work out of the crypt inner
> > loop and do it during set_key for cheaper. Also a small amount of work
> > could be moved into crypt (to vectorize it). It's not a huge difference,
> > but I think it's obviously correct.
> > 
> > https://github.com/magnumripper/JohnTheRipper/pull/280/files
> 
> This is merged.

Thanks! BTW, I saw your recent commit adding omp support to raw-sha256-ng, I
tried to copy and paste your code, but I get this odd result:

$ ../run/john -test -fo=raw-sha1-ng
Benchmarking: Raw SHA-1 (pwlen <= 15) [128/128 SSE4.1 intrinsics
4x]...(8xOMP) DONE
Raw:	23232K c/s real, 3338K c/s virtual

I don't understand why real is so different than virtual, compared to
without omp:

$ ../run/john -test -fo=raw-sha1-ng
Benchmarking: Raw SHA-1 (pwlen <= 15) [128/128 SSE4.1 intrinsics 4x]... DONE
Raw:	9251K c/s real, 9251K c/s virtual

What am I doing wrong? (I already batch crypts, so I figured I could just
split the work across threads if available, maybe this was naive).

https://github.com/taviso/JohnTheRipper/commit/49f45735aafb38d49308009f3e135825979374b5

> 
> 
> > BTW, would you like me to look into handling longer passwords without
> > burning cycles for the common (len <= 15) case? I don't think it's
> > possible to do it for free, but maybe it won't be too expensive.
> 
> 
> That would be nice, and then we'd give it higher precedence than the
> slower raw-sha1 so auto-loading would pick your format.
> 
> Technically, we could let John chose format at init, based on --min-length
> and --max-length if given. But that would probably just be confusing.
> 
> magnum
> 

OK, will do.

Tavis.


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