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Date: Sun, 18 Mar 2012 08:39:24 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: SSH thread-safety

On Sun, Mar 18, 2012 at 04:45:24AM +0400, Solar Designer wrote:
> Here's what I get on FX-8120 at stock clocks (3.1 GHz base, 4.0 GHz turbo):

Apparently, the documented base frequency is not relevant when the CPU
is under load and not overheated.

http://en.wikipedia.org/wiki/List_of_AMD_FX_microprocessors gives 3.1 GHz
base, 3.4 GHz full load turbo, and 4.0 GHz half load turbo for this CPU.
In the BIOS overclocking settings, I can only specify two values for the
multiplier: base and turbo.  I've just tried setting base to 4.0 GHz and
disabling turbo (so should be 4.0 GHz as well) - got an unreliable
system (kernel panic shortly after starting to use XOP from all 8
threads).  Then I tried 3.8 GHz base and 4.2 GHz turbo - and this seems
to work.  I am getting almost exactly a 5% speedup for single-threaded
benchmarks and around a 10% speedup for OpenMP benchmarks (although it
varies between the different JtR formats).  Thus, it appears that
without overclocking I had 3.4 and 4.0, and now I have 3.8 and 4.2 GHz.

> Non-OpenMP build:
> 
> user@...l:~/john/magnum-jumbo/src$ ../run/john -te -fo=ssh
> Benchmarking: ssh [32/64]... DONE
> Raw:    146448 c/s real, 146448 c/s virtual

Benchmarking: ssh [32/64]... DONE
Raw:    153300 c/s real, 153300 c/s virtual

> OpenMP:
> 
> user@...l:~/john/magnum-jumbo/src$ ../run/john -te -fo=ssh
> Benchmarking: ssh [32/64]... (8xOMP) DONE
> Raw:    717852 c/s real, 89196 c/s virtual

Benchmarking: ssh [32/64]... (8xOMP) DONE
Raw:    793987 c/s real, 98967 c/s virtual

BTW, FX-8150 is documented to use 3.6 base / 3.9 full load turbo / 4.2
half load turbo, so maybe I should try 3.9 / 4.2.

Alexander

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