Date: Wed, 18 Mar 2015 17:27:45 +0800 From: Lei Zhang <zhanglei.april@...il.com> To: john-dev@...ts.openwall.com Subject: Re: [GSoC] building JtR for MIC Hi, I tweaked with OMP_SCALE in several formats, according to magnum's advices, and their memory usage on MIC is much more reasonable now. With OpenMP enabled, john-jumbo won't abort anymore when running the benchmark, although 126 of the tests still FAILED. Next I want to figure out how those tests failed, but I have a few questions first: (forgive me if they look stupid...) 1. What exactly does it mean for a format to FAIL the test? 2. There're two kind of numbers in the output, real and virtual. What's their difference? Thanks, Lei > On Mar 18, 2015, at 12:22 AM, magnum <john.magnum@...hmail.com> wrote: > > On 2015-03-17 10:38, Lei Zhang wrote: >> I reran the benchmarks on MIC, with or without OpenMP, and got some statistics. >> >> *With OpenMP:* >> The result is a bit different from last time. The program didn't get killed when >> running /mschapv2-naive/, but aborted later when running /mysql/, with error >> message: *****mem_alloc(): Cannot allocate memory trying to allocate 5190451200 >> bytes***** > > Wow that's pretty heavy for a single allocation. Note the following > lines in mysql_fmt_plug.c: > > #define OMP_SCALE 81920 > (...) > #define MAX_KEYS_PER_CRYPT 8 > > This is your problem. You will ending up allocating 81920*8*240*33 bytes > for the plaintext buffer (btw the "33" is [PLAINTEXT_LENGTH + 1]). > > So this OMP_SCALE is obviously not suitable for MIC. Try something like this > > + #ifdef __MIC__ > + #define OMP_SCALE 128 > + #else > #define OMP_SCALE 81920 > + endif > > Then you may tweak it by doubling it until it doesn't get faster (or > just gets silly high). > > Nearly all OpenMP formats use this exact scheme so you can fix most > formats the same way. I'm pretty sure the NETLM* and NETNTLM* formats > are just as bad or worse. > > magnum > >
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