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Message-ID: <20061005063206.GA18804@openwall.com>
Date: Thu, 5 Oct 2006 10:32:06 +0400
From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com
Subject: Re: Re: JTR and os X macintel
On Thu, Oct 05, 2006 at 05:53:47AM +0000, -. -PhanTom-. - wrote:
> Oh well, AMD has been known as the king of
> Floating Point Operations in the past, they will be again... I guess
This has nothing to do with JtR since it does not use floating point
operations at all.
> > > I was under the impression that the high speeds on Macs were due to the
> > > G4 and G5 cpus and that the OS had very little to do with it...?
> >
> > Correct.
>
> Does this apply to Linux vs Windows as well?
Yes - there should be almost no performance difference for JtR on Linux
vs. Windows (except for Windows 9x/ME and older).
> As far as I could tell, latest version of JTR would theoretically yield
> higher speeds on linux64 on an AMD64 cpu compared to windows...
I have to be guessing as to where you derived this conclusion from. We
had a discussion in here some months ago where you wanted to make a
64-bit build of JtR on Windows - and that is not currently supported.
So you could not see whether your CPU would yield better performance
when running the x86-64 16-register SSE2 code vs. the plain x86
8-register SSE2 code. I suggested that you try on a Linux/x86-64
system. I did not imply that the 16-register version would be faster
for you - although it might be.
> However, I did test this and saw no higher speeds on Linux64 compared to
> windows32.... could be related to compilation though..not sure...
It is entirely possible that the 16-register version is not any faster
on your CPU. In fact, it may even be a little bit slower, such as
because of the extra instruction prefixes. Either way, the difference
should be within 10% - anything beyond that would be abnormal.
Please note that SSE is 128-bit (at least from the application's point
of view) regardless of whether you build for 32-bit or 64-bit.
--
Alexander Peslyak <solar at openwall.com>
GPG key ID: 5B341F15 fp: B3FB 63F4 D7A3 BCCC 6F6E FC55 A2FC 027C 5B34 1F15
http://www.openwall.com - bringing security into open computing environments
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