openwall / openwall/john

OpenCL autotune: use a subset of test vectors

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enhancement
Dominant language
C
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Description

Originally written as comment https://github.com/magnumripper/JohnTheRipper/pull/3627#issuecomment-459991983

It looks like autotune is doing a worse job with the revised md5crypt-opencl kernel, perhaps because our test vectors differ from actual passwords and hashes so much.

It'd be very useful for us to be able to specify a reduced set of test vectors for autotune and benchmarks. For the benchmarks, we have related issue #3625. This one is for autotune.

Also, when running with specific password length(s) - such as with mask mode and/or with min/max lengths specified with command-line options or for an incremental mode - maybe the autotune could limit itself to using test vectors that fall within this lengths range?

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Research direction

Start by tracing how autotune selects test vectors and how password-length ranges are represented for mask and incremental modes. Compare the proposed autotune behavior with related benchmark issue #3625. Done means autotune can use an appropriate reduced or length-matched vector subset without changing unrelated benchmark behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
performance
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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