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Date: Wed, 15 Feb 2012 19:26:08 +0400
From: Solar Designer <>
Subject: Re: OMP version not use all CPU

On Wed, Feb 15, 2012 at 06:56:03AM -0800, Alain Espinosa wrote:
> You are right, john-omp is working as expected. I see a 25% CPU use in
> the Task Manager and think i john was using only one core. More info
> by Resource Monitor (happen the same with jumbo and non jumbo
> version):
> When using 2 threads there is 2 cores (logical cores) with 0% use, 1
> with 25% and other with 75%.
> When using 4 threads there is 2 cores (logical cores) with 0% use and
> the other 2 with 50%.

Yes, OpenMP parallelization efficiency is very poor for fast hashes, and
especially on Windows.  It is mostly meant for slow(er) hashes currently -
e.g., we're getting nearly 100% efficiency at bcrypt, but obviously it
is irrelevant for your benchmarks vs. Hash Suite currently.

What c/s rates are you getting for these tests, though?  I am interested
in both --test and actual runs.

> I review all the process of benchmarking and found my reported
> performance accurate. Here is john -test:
> >..\john.exe -test --format:nt
> Benchmarking: NT MD4 [128/128 SSE2 + 32/32]... DONE
> Raw:    18412K c/s real, 18412K c/s virtual
> >..\john.exe -test --format:nt2
> Benchmarking: NT v2 [SSE2i 12x]... DONE
> Raw:    21509K c/s real, 21509K c/s virtual
> >..\john.exe -test --format:lm
> Benchmarking: LM DES [128/128 BS SSE2]... DONE
> Raw:    29076K c/s real, 29459K c/s virtual
> >..\john.exe -test --format:mscash
> Benchmarking: M$ Cache Hash [Generic 1x]... DONE
> Many salts:     14939K c/s real, 14939K c/s virtual
> Only one salt:  5845K c/s real, 5845K c/s virtual


I thought the speed at LM would be higher on your CPU, but it seems not.
I am getting 40M c/s on a several years older 2.5 GHz CPU (no OpenMP),
but that's with a 64-bit build.



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