Date: Sat, 18 Apr 2015 23:59:58 +0200 From: Agnieszka Bielec <bielecagnieszka8@...il.com> To: john-dev@...ts.openwall.com Subject: Re: [GSoC] John the Ripper support for PHC finalists 2015-04-18 20:45 GMT+02:00 Agnieszka Bielec <bielecagnieszka8@...il.com>: > If benchmark encrypts one password on various gws, bencharking will > give better result than it should be due to less random memory access > I'm trying to investigate this It's true. All the time I was receiving wrong benchmarking results because if we have the same password to encrypt in various GPU's units function H which randomly accesses the memory works faster due better coalescing I made an experiment. previously I wrote: > if in fmt_test are 2 records, it is fast > when I add 10 records with the same cost, it slows down If I remove function H from the kernel all the time the speed is the same I've modified the file bench.c to random all keys and I think I've received true results now [a@...er run]$ ./john --test --format=pomelo-opencl --dev=1 --cost=2:2,2:2 Benchmarking: pomelo-opencl, POMELO [POMELO OpenCL (inefficient, development use only)]... max cost 2 Device 1: Tahiti [AMD Radeon HD 7900 Series] Local worksize (LWS) 64, global worksize (GWS) 4096 DONE Speed for cost 1 (N) of 2, cost 2 (r) of 2 Raw: 80313 c/s real, 8192K c/s virtual [a@...er run]$ ./john --test --format=pomelo-opencl --dev=5 --cost=2:2,2:2 Benchmarking: pomelo-opencl, POMELO [POMELO OpenCL (inefficient, development use only)]... max cost 2 Device 5: GeForce GTX TITAN Local worksize (LWS) 64, global worksize (GWS) 8192 DONE Speed for cost 1 (N) of 2, cost 2 (r) of 2 Raw: 82671 c/s real, 82671 c/s virtual not as bad ( comparing to previous ) in my opinion I think that there are 3 possible solutions 1). modify bench.c like I've modified (but, are there a hashes which cannot receive some specific password values? ) 2). spefify more tests cases for fmt_tests (but, sometimes we will need to pass 100 tests cases and sometimes more) 3). make fmt_main to generate password values if the answer in question is yes what are your opinions? BTW I think that I should make some charts comparing the speed of GPU with CPU in the future thanks
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