Date: Fri, 06 Jan 2012 01:33:33 +0100 From: magnum <john.magnum@...hmail.com> To: john-dev@...ts.openwall.com Subject: Re: MD5 intrinsics compile-time condition > I just checked in (to github) a patch that adds two make targets > (testpara and testpara32) for determining the best SSE_PARA values for a > particular system. > > It's a hack but it seems pretty accurate. Some notes about this hack, there's lots of room for improvement: 1. It does five runs and use a simple average of the results. On most computers I've run it, this is not needed - but on a Q9550 (Mint 12 desktop, no load) the figures (for more or less any JtR benchmark) fluctuates wildly. Sometimes so much, I have to re-run testpara anyway (three runs may show a 50% drop compared to the other two, for no obvious reason). 2. It does not pick a higher PARA unless the gain was 5% or more. This might be too conservative. The rationale was that a too high para (if using the results on a different system) usually does much more harm than a slightly too low. 3. Obviously, you can put icc or clang in the CC line on top of Makefile with no further tweaks: model name : Intel(R) Core(TM)2 Duo CPU P8600 @ 2.40GHz gcc version: clang (clang version 2.9 (tags/RELEASE_29/final)) Best paras: raw-MD4: 4 (36374K c/s) crypt-MD5: 4 (22646 c/s) raw-SHA1: 2 (11014K c/s) magnum
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