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Date: Thu, 25 Mar 2010 22:58:03 +0100
From: "Magnum, P.I." <>
Subject: bench.c fix for extreme c/s figures

First I thought I'd post Solar directly with this, but other readers may 
have an idea, so here goes:

Running under MPI, I experienced c/s rollover even from just a couple of 
seconds of NT benchmarking. The problem was only when benchmarking, not 
real cracking. I identified it as due to the sloppy conversion in this 
line in benchmark_cps() in bench.c:

     tmp.lo = count; tmp.hi = 0;

Enclosed is the dilettant take I made to make it better (along with some 
more scaling, to mega and giga c/s) which was included in fullmpi-5. 
This should apply more or less cleanly to standard john too. This fix 
works just fine on my gear, but W.A's OSX system (using 64-bit longs and 
presumably the same for ARCH_WORD) now reportedly produces figures of 
"4294M c/s" for both real and virtual and for all and any formats, 
whether fast or not and even when running on just one node.

I'm willing to admit I am the worst coder on earth but while I recognize 
that figure, I don't really see what went wrong?

Moore's law will make this problem real even for non-mpi john soon so 
it's not just an MPI problem for very long :)


View attachment "bench.c.patch" of type "text/x-patch" (1180 bytes)

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