Date: Fri, 21 Aug 2015 09:16:00 +0800 From: Kai Zhao <loverszhao@...il.com> To: john-dev@...ts.openwall.com Subject: Re: BENCHMARK_LENGTH bugs On Fri, Aug 21, 2015 at 1:30 AM, magnum <john.magnum@...hmail.com> wrote: > On 2015-08-20 19:13, Kai Zhao wrote: >> >> On Mon, Aug 17, 2015 at 11:22 PM, Solar Designer <solar@...nwall.com> >> wrote: >>> >>> Also, identify formats that wrongly set BENCHMARK_LENGTH to 0 when they >>> don't actually need to report separate "Many salts" vs. "Only one salt" >>> speeds (that is, formats that are very slow or/and saltless, so the two >>> speeds reported are nearly the same anyway). > > >> >> I create a patch for benchmark_length: >> >> >> https://github.com/loverszhaokai/JohnTheRipper/commit/810a62c938d86a724f5398d312bbb1c5736a1147 > > >> Testing: 7z, 7-Zip (512K iterations) [SHA256 AES 32/64]... (8xOMP) >> FAILED (This format is very slow, but it will report separate "Many >> salts" vs. "Only one salt" speeds) > > > Your patch has a hard-coded list of "slow hashes". That's not good > from any point of view. As seen in the above figures, you should do > calculate a figure many/one like this: > >> $ ../john --test --format=7z >> >> Will run 8 OpenMP threads >> Benchmarking: 7z, 7-Zip (512K iterations) [SHA256 AES 32/64]... (8xOMP) >> DONE >> Speed for cost 1 (iteration count) of 524288 >> Many salts: 3056 c/s real, 3034 c/s virtual >> Only one salt: 18.0 c/s real, 18.1 c/s virtual > > > 3056/18 = 169.78x faster. Definitely nothing to complain about. > >> $ ../john --test --format=dominosec8 >> >> Will run 8 OpenMP threads >> Benchmarking: dominosec8, Lotus Notes/Domino 8 [8/64]... (8xOMP) DONE >> Warning: "Many salts" test limited: 1/256 >> Many salts: 3471 c/s real, 435 c/s virtual >> Only one salt: 3303 c/s real, 416 c/s virtual > > > 3471/3303 = 1.05x so a 5% speedup. I'm not sure we should complain even > here. > > I think you should complain if speedup is less than 1-2%. Also, I'm not sure > you should FAIL but maybe just "Warning: ..." like with alignment issues. > Solar? I think I misunderstood the "slow" which I thought it was the formats whose real speed was small. As magnum said, the "slow" means the speedup from "Only one salt" to "Many salts" is less than 1-2%. But there are many formats whose benchmark_length is '-1', and they only have "Raw" speed. How to judge whether these formats are slow? Thanks, Kai
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