Date: Thu, 26 Sep 2013 00:14:16 +0200 From: magnum <john.magnum@...hmail.com> To: "john-dev@...ts.openwall.com" <john-dev@...ts.openwall.com> Subject: External node distribution (call for help) Solar, all, The enclosed patch avoids the modulo operation in External mode when distributing work using node/fork/MPI. The speedup depends on several parameters but I've seen 10-15% for 8 nodes. This is the same scheme that I now use in mask mode. The downside is that the patch (once you enable it by uncommenting the #define) changes the session file format for External mode so it will be incompatible with core. However, there is a way to avoid changing the file format: We could read a "seq" number from file and convert it to "my_words" and "their_words". And vice versa when saving. That should be fairly easy (although I haven't really tried it yet) BUT what if the session was started on core John, and "seq" wrapped around it's 32 bits once or several times? And only then we resume it using the new code... and let's say our number of nodes is a prime... Would this mean our conversion might not be valid? Or can I totaly ignore such wrapping? I haven't figured that out yet %-) magnum View attachment "0001-Faster-node-fork-MPI-distribution-for-External-mode..patch" of type "text/plain" (3464 bytes)
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