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Date: Thu, 17 Sep 2015 16:15:40 +0200
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: Re: Judy array

On 2015-09-16 01:05, Solar Designer wrote:
> On Wed, Sep 16, 2015 at 12:43:44AM +0200, magnum wrote:
>> Also, I don't observe any gain from disabling mmap and only minimal gain
>> from using --mem=0 when mmap is enabled (I stopped using -mem after mmap
>> was implemented). I'm surprised by your results (...)

> Let me re-test...
>
> First, I took the latest cracker.c.  This got my prefetching disabled.
> And, surprise, it's now 2 seconds slower (I still have SHR=0):
>
> real    0m58.804s
> user    4m26.433s
> sys     0m18.934s
>
> Maybe the prefetching is sometimes helping, after all, even though for
> our current raw-md5 it's very limited (max_keys_per_crypt is only 12, so
> those loops don't actually go to the hard-coded maximum of 64
> outstanding prefetches).
>
> Now, enabling mmap (still no prefetch, etc.):
>
> real    1m0.847s
> user    4m51.136s
> sys     0m15.579s
>
> In both cases, I also had -mem=0 on the command line.

Here's a theory: Does the E5420 have a significant penalty for unaligned 
SIMD loads? If so, you should try this (wordlist.c:140)

-#if defined(SIMD_COEF_32) && !defined(_MSC_VER) && \
+#if 0 && defined(SIMD_COEF_32) && !defined(_MSC_VER) && \

The alternative code might be faster.

magnum

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