Date: Fri, 25 May 2012 00:25:53 +0200 From: magnum <john.magnum@...hmail.com> To: john-users@...ts.openwall.com Subject: Re: Can Excessive Rounds make Password cracking Infeasable On 05/24/2012 11:03 PM, Solar Designer wrote: > On Thu, May 24, 2012 at 10:49:41PM +0200, magnum wrote: >> FWIW, some very quick tests on Solar's test gear with the hash above: >> >> CPU (8 cores): 4.75 c/s >> GTX580: 4300 c/s >> HD7970: 6000 c/s >> > These GPU speeds are not realistic. There must be a bug or just lack of > support for non-default numbers of iterations for this hash type (this > is something for us to correct if so!) That support is there. It turns out I did the CPU test above on just one core but the figures are still not plausible. I now modified the formats with an actual test vector with 391939 rounds, so we see that they are doing it right. This also give me correct c/s figures directly (I had to recalculate the ones above as discussed on john-dev). For some reason, CUDA now took forever so I modified the self-tests to only do one test instead of a subset of max_keys_per_crypt (I hardcoded max=1). New figures: Benchmarking: crypt SHA-512 (rounds=391939) [OpenSSL 64/64]... (8xOMP) DONE Raw: 26.3 c/s real, 3.3 c/s virtual Benchmarking: cryptsha512-cuda (rounds=391939) [SHA512-based CRYPT]... DONE Raw: 49.7 c/s real, 49.7 c/s virtual (we might be able to bump the CUDA figure but I don't have time for that. Ideally CUDA formats should auto tune like the OpenCL formats do) Using device 0: GeForce GTX 570 Benchmarking: crypt SHA-512 (rounds=391939) [OpenCL]... DONE Raw: 4185 c/s real, 4185 c/s virtual Using device 0: Tahiti Benchmarking: crypt SHA-512 (rounds=391939) [OpenCL]... DONE Raw: 5285 c/s real, 3276K c/s virtual Using device 1: AMD FX(tm)-8120 Eight-Core Processor Benchmarking: crypt SHA-512 (rounds=391939) [OpenCL]... DONE Raw: 1873 c/s real, 234 c/s virtual This last test should confirm that something's not right. I believe OpenCL CPU can't be 70x OMP... Whatever is wrong with Claudio's format, it's not caught by the self-tests. We need to implement cryptsha in the test suite :( > Also, I guess you were not running Claudio's latest OpenCL code, which > should do 11.5k c/s on GTX 570 at rounds=5000. It turns out I was. Not sure what is happening here. magnum
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