john-dev - About very high memory usage

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Date: Thu, 5 Jul 2012 11:24:59 +0800
From: myrice <qqlddg@...il.com>
To: john-dev@...ts.openwall.com
Subject: About very high memory usage

I find JtR will use very high memory in real test. Here is what I observed:

In my xsha512-cuda, I set MIN_KEYS_PER_CRYPT=MAX_KEYS_PER_CRYPT =
128*1024. So it allocates 128*1024 keys and hashes.
    For each key, we have 125 char and a byte of length which is
totally 126 bytes.
    For each hashes, we have 1 uint64_t which is 8 bytes.
    So we have 128KB*(126+8) = 16.75MB
    However, when I do ./john -te=xsha512-cuda
../jtrTestSuite/XSHA512_tst.in . The john uses up to 4.4GB memory on
bull.

I also changed format XSHA512, set
MIN_KEYS_PER_CRYPT=MAX_KEYS_PER_CRYPT = 128*1024. The situation is the
same.

Besides, in self test or if I gave a wordlist to john, mean I do
./john -te=xsha512-cuda ../jtrTestSuite/XSHA512_tst.in
-wo=../jtrTestSuite/pw.dic, it will not take so much memory.

I just curious about it. Does single or incremental mode uses so much memory?

Thanks
myrice

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