Date: Tue, 26 Jun 2012 10:06:47 +0200 From: magnum <john.magnum@...hmail.com> To: john-dev@...ts.openwall.com Subject: Re: mschap-v2 conversion On 2012-06-26 09:16, deepika dutta wrote: > 1) I want to know the meaning of Thread_ratio and how the values of > Thread_ratio and Max_keys_per_crypt are being decided? Is it fixed by > you or is being decided based on some factor? > > #define MIN_KEYS_PER_CRYPT 1 > #define THREAD_RATIO 256 > #ifdef _OPENMP > #define MAX_KEYS_PER_CRYPT 0x10000 > #else > #define MAX_KEYS_PER_CRYPT THREAD_RATIO > #endif I picked THREAD_RATIO from trial'n'error. For a very slow format it can be lower, for faster formats it need to be higher. > 2) Without openmp: With openssl des, Thread_ratio (256) keys were > read and used for encryption at a time. But with bitsliced des at a > time only DES_BS_DEPTH keys can be used, so whether I should change > the MAX_KEYS_PER_CRYPT parameter to DES_BS_DEPTH (which I have done > for now in my patches) or I should keep it to Thread_ratio but > process des_bs_depth keys at one go? In your case you should probably look at how this is implemented in DES_fmt.c (but it's harder to follow). > 3) With openmp: For openmp Max_keys_per_crypt is 16 according to > #define value, also in init() n is set to MAX_keys_per_crypt if > greater than that. According to my understanding, this means that16 > keys will be read and used at a time and thus bitslicing and openmp > will not give any benefit as only 1 core will be in use with only 16 > out of DES_bs_DEPTH layers being used. Therefore, this parameter > needs change. Correct me if i am wrong. This code was written without bitslice in mind, I guess you need to replace some of it. I think you might already have some good #defines from DES_bs.h that you can use but I don't really know that code. Solar may respond much better when he gets some more time. magnum
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