Date: Sat, 13 Jul 2013 20:16:02 -0300 From: Claudio André <claudioandre.br@...il.com> To: john-dev@...ts.openwall.com Subject: Re: bug: GPU use in CPU-only formats > magnum, Claudio - > > This problem is still present, and it manifests itself in an even worse > way than I had thought. Not only is there some use of the first GPU > during CPU-only runs with an OpenCL-enabled build, but also CPU time is > being wasted by some OpenCL-related overhead, which slows down CPU-based > cracking (in some of my tests, by more than a factor of 2 - that's when > OpenMP is also in use). This is easily reproducible on our new dev box > (which I'll create you accounts on shortly), where several ksoftirqd > kernel threads appear high in "top" when running a CPU-only format in an > OpenCL-enabled build of JtR. > > Alexander Is it possible to reproduce this on bull easily? What i saw is listed below: -opencl is slower than -gpu? Doesn't make sense. But it is, even after the attached patch (no more OpenCL code). I saw nothing inside Makefile. Have you tried unstable? I tried -native, -gpu, -opencl: ../run/john -form:sha512crypt -t=20 -native Benchmarking: sha512crypt, crypt(3) $6$ (rounds=5000) [SHA512 64/64 OpenSSL]... (8xOMP) DONE Raw: 2055 c/s real, 257 c/s virtual -gpu Benchmarking: sha512crypt, crypt(3) $6$ (rounds=5000) [SHA512 64/64 OpenSSL]... (8xOMP) DONE Raw: 2051 c/s real, 256 c/s virtual -opencl (the best) Benchmarking: sha512crypt, crypt(3) $6$ (rounds=5000) [SHA512 64/64 OpenSSL]... (8xOMP) DONE Raw: 2018 c/s real, 252 c/s virtual Claudio ---- diff --git a/src/Makefile b/src/Makefile index 7efd253..d5e9e6a 100644 --- a/src/Makefile +++ b/src/Makefile @@ -32,7 +32,7 @@ SORT = sort OMPFLAGS = # gcc with OpenMP -#OMPFLAGS = -fopenmp +OMPFLAGS = -fopenmp # gcc with OpenMP on 32-bit x86 with SSE2 #OMPFLAGS = -fopenmp -msse2 # Mac OS X (llvm-gcc) with OpenMP diff --git a/src/john.c b/src/john.c index 689b282..4dbdb3f 100644 --- a/src/john.c +++ b/src/john.c @@ -1068,7 +1068,7 @@ static void john_init(char *name, int argc, char **argv) listconf_parse_late(); #ifdef HAVE_OPENCL - opencl_preinit(); +// opencl_preinit(); #endif common_init(); @@ -1212,8 +1212,8 @@ static void john_done(void) } log_done(); #ifdef HAVE_OPENCL - if (!(options.flags & FLG_FORK) || john_main_process) - opencl_done(); +// if (!(options.flags & FLG_FORK) || john_main_process) +// opencl_done(); #endif path_done(); Content of type "text/html" skipped
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