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Date: Sun, 27 Jan 2013 20:09:43 -0500
From: Brian Wallace <nightstrike9809@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: Proposed optimizations to pwsafe

When I applied the opencl optimization, I only saw minor improvements
compared to the CUDA improvements.  I found that was kind of weird, because
it was basically the same changes to the code.

On Sun, Jan 27, 2013 at 7:58 PM, magnum <john.magnum@...hmail.com> wrote:

> On 28 Jan, 2013, at 1:41 , Solar Designer <solar@...nwall.com> wrote:
> > On Sun, Jan 27, 2013 at 07:22:19PM -0500, Brian Wallace wrote:
> >> Ok, I'll do those changes.  I haven't done much cuda/ocl coding in the
> >> past, so it might take me a short while to get up to speed on what works
> >> best, although I have a good background in C and hash cracking
> >> optimization.  What kind of benchmarks are we getting on pwsafe-opencl
> vs
> >> hashcat.
> >
> > Apparently, hashcat's speed is ~500k on HD 7970.  hashkill is at ~480k:
> >
> > http://twitter.com/gat3way/status/294968226209726464/photo/1
> >
> > We're getting 355k:
> >
>
> > (The match of OpenCL and CUDA speed is curious.  I did not tune THREADS
> > and BLOCKS in cuda_pwsafe.h, and was compiling for the default of sm_10.
> > Perhaps better speed is possible with some tuning.)
>
> The OpenCL format currently only auto-tunes local work-size (THREADS) so
> it too runs at suboptimal conditions. The global work-size defauls to the
> same figure the CUDA format use. It does support LWS/GWS environment
> variables though:
>
> $ GWS=$((256*1024)) ../run/john -t -fo:pwsafe-opencl -plat=1
> OpenCL platform 1: AMD Accelerated Parallel Processing, 2 device(s).
> Device 0: Tahiti (AMD Radeon HD 7900 Series)
> Local worksize (LWS) 64, Global worksize (GWS) 262144
> Benchmarking: Password Safe SHA-256 [OpenCL]... DONE
> Raw:    362411 c/s real, 78643K c/s virtual
>
> No huge difference though.
>
> In bleeding, Claudio has added a shared function for tuning GWS. I haven't
> had time to try it out yet.
>
> magnum
>

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