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Date: Tue, 5 May 2015 19:09:58 +0300
From: Solar Designer <>
Subject: Re: Lei's weekly report #1

On Tue, May 05, 2015 at 06:02:46PM +0200, Lukas Odzioba wrote:
> 2015-05-05 14:06 GMT+02:00 Lei Zhang <>:
> > - Try to make MIC offload mode work in JtR core.
> In my opinion this is similar to multigpu support for gpu formats and
> shouldn't have high priority (not higher than getting maximum native
> performance),

I agree.  This is a side project.  We should limit time spent on it.

> or maybe you can provide more interesting use case
> scenarios where it makes sense to use offload (like mixing cpu and
> offloaded mic in the same format).

It may be handy to use offload even with just one MIC card, because with
offload the files naturally stay on the host system.  A drawback of
running on the MIC card natively (non-offload) is that by default all
files reside on the MIC card's ramdisk, so are lost on reboot (unless
explicitly copied from there).  This is avoided with an NFS mount from
host, but it takes some sysadmin effort to set it up.

Unfortunately, it appears that offload won't provide adequate
performance given JtR's current rather low level use of OpenMP, except
for very slow hashes like bcrypt.  For descrypt, as currently
implemented in JtR, I expect offload will be painfully slow.


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