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Date: Sun, 8 Jul 2012 09:35:31 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: Between 1.7.9-jumbo-3 and 1.7.9-jumbo-4 performance of --format=bf dropped by more than 20%

On Sun, Jul 08, 2012 at 12:13:54AM +0200, Frank Dittrich wrote:
> I tested generic, which brought back the old bf speed.
> 
> May be we could point out in doc/INSTALL, that we tried to find optimal
> settings for the build targets listed, but that for a few exceptions a
> generic build can be faster for a particular benchmark than the "most
> common" build target for an architecture.

Maybe.  Or we could simply introduce an -atom target, as long as that's
what we're facing the issues with.  We could include this optimization
for DES as well:

http://www.openwall.com/lists/john-users/2010/06/28/1

> For the jumbo build, we could even point out that trying alternative
> compilers like clang vs. gcc or different gcc versions can make a
> siginificant difference for those (new) formats which have not been that
> much optimized than the core formats.

I think this is what people assume by default.  In fact, we heard from a
lot of people trying different compilers before and making (wrong)
conclusions based on the lack of a change in performance - that was when
x86 builds were almost 100% assembly for the performance-critical parts.

Alexander

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