Date: Mon, 8 Aug 2011 15:22:44 +0200 From: Lukas Odzioba <lukas.odzioba@...il.com> To: john-dev@...ts.openwall.com Subject: Lukas's Status Report - #13 of 15 Last week I've: -optimized phpass,sha-crypts patches -retested them before contest -cracked some passwords with john-users team -fixed 2 GPU problem on my system, I thougth that it was drivers fault but problem laid in 32bit kernel. Adding vmalloc=256MB fixed X's problem. This week: -fix/test OpenCL build problems -test phpass more extensively -work on previous (unfinished) patches Thoughts: I think that from now it will be better keep cuda patches together like in "allcuda" patch, because it is easier to manage one version. I couldn't find good name for it when I was uploading to the wiki, but now I think it "slowcuda" is better name. Today I've did some changes on phpasscode and got 5% more power from it. I had to duplicate whole MD5 block but it is not using any external memory during main processing. I found on Ivan Golubev's blog (http://www.golubev.com/blog/?tag=gtx460) interesting information about GF104 and newer nvidia chips saying: "But main thing that you’re need to vectorize your code for GF104 (and 106/108) to get full performance of GPU as it already happens with ATI GPUs. Processing single hash per thread will drop performance by 2/3 (for algorithms which instructions heavily depends on each other, like MD5), thus making 336SP of GTX460 looking like only 224SP. There are a lot of another changes at GF104 but they aren’t so important for hash calculations like code vectorization." That gives me hope for further cuda patches optimizations in the near future. >From benchmarks posted on ml of GTX480 it's clear that phpass code is alu-bounded, and scales great on more powerfull graphics cards, while MD5-crypt and SHA-crypts still have got memory bottleneck which I must get rid off, or at least minimize. This explain why modyfing MD5's F() and G() functions did not help at md5crypt exactly as Solar stated earlier (but helped for phpass). Groszek and Solar reported problems with phpass used during the contest, I need to investigate it too. Lukas
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