Date: Mon, 25 Jun 2012 02:06:14 +0400 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: Re: Why the PHPS benchmark change from Many salts/Only one salt to Raw since jumbo-5? Frank, all - On Sun, Jun 24, 2012 at 11:46:46PM +0200, Frank Dittrich wrote: > Is there a reason why the single salt / many salts case shouldn't be > relevant anymore? There's only one test vector in PHPS_fmt_plug.c, so the "many salts" benchmark wouldn't be reasonable. A recent change to bench.c recognizes this special case now. We need to add more test vectors. In general, having only one test vector is wrong, yet this is the case for many formats currently. > For jumbo 5, there's a large difference for many salts/only one salt, This is puzzling. A bug? Here's what I get with magnum-jumbo from a few days ago, prior to the bench.c change: Benchmarking: PHPS md5(md5($pass).$salt) [128/128 XOP intrinsics 16x4x2]... DONE Many salts: 30907K c/s real, 30907K c/s virtual Only one salt: 9006K c/s real, 9006K c/s virtual And with current magnum-jumbo: Benchmarking: PHPS md5(md5($pass).$salt) [128/128 XOP intrinsics 16x4x2]... DONE Raw: 30619K c/s real, 30619K c/s virtual So we're getting the better one of the two speeds now, and I think it actually corresponds to having a fixed password, so md5($pass) probably gets precomputed. We really need to add more test vectors to get reasonable benchmark results. Alexander
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