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Date: Fri, 14 Jun 2019 08:23:30 -0400
From: billwhittaker@...e-mail.net
To: john-users@...ts.openwall.com
Subject: Re: Unable to use OpenCL on arm64v8/debian stretch
> > ../run/john --test --format=opencl
> > Device 1@...i: Mali-T860
> > Benchmarking: sha1crypt-opencl, (NetBSD) [PBKDF1-SHA1 OpenCL 4x]... DONE
> > Speed for cost 1 (iteration count) of 64000 and 40000
> > Raw: 12.5 c/s real, 2560 c/s virtual
>
> This shows that *some* formats does work fine, so your OpenCL
> installation isn't totally broken.
You consider 12.5 c/s to be "working fine" despite the speed? You do not believe the driver is the cause of such inefficiency?
> That benchmark speed is pretty low though, my laptop GPU does 10510 c/s
> with that format. What if you add --force-scalar to the command line? By
> default, some formats will use 4x vectorizing because your runtime
> claims that's the preferred width of int, but it doesn't always end up
> faster.
Without pocl
./run/john --test --format=opencl --force-scalar
Device 1@...i: Mali-T860
Benchmarking: sha1crypt-opencl, (NetBSD) [PBKDF1-SHA1 OpenCL]... DONE
Speed for cost 1 (iteration count) of 64000 and 40000
Raw: 112 c/s real, 6400 c/s virtual
With pocl, my CPU appears as a device.
Device 1@...i: Mali-T860
Benchmarking: sha1crypt-opencl, (NetBSD) [PBKDF1-SHA1 OpenCL]... DONE
Speed for cost 1 (iteration count) of 64000 and 40000
Raw: 113 c/s real, 8533 c/s virtual
I do not know why I am seeing 112/113 now, but saw only 12 earlier.
The CPU outperforms the GPU.
../run/john --test --format=sha1crypt
Will run 6 OpenMP threads
Benchmarking: sha1crypt, NetBSD's sha1crypt [PBKDF1-SHA1 128/128 ASIMD 4x]... (6xOMP) DONE
Speed for cost 1 (iteration count) of 64000 and 40000
Raw: 234 c/s real, 48.1 c/s virtual
Shouldn't the results be vice-versa, with the GPU outperforming the CPU?
(Redundant with question prior.) Could the runtime/driver for the GPU somehow cause such a low c/s?
> Anyway I'd start with looking for OpenCL driver/runtimer updates unless
> you already did so.
As far as I can tell, I have a choice: Mali drivers for opencl
dpkg -l |grep opencl
ii ocl-icd-libopencl1:arm64 2.2.11-1 arm64 Generic OpenCL ICD Loader
ii opencl-c-headers 2.1-1 all OpenCL (Open Computing Language) C header files
dpkg -l |grep mali
ii liblognorm5:arm64 2.0.1-1.1+b1 arm64 log normalizing library
ii libmnl0:arm64 1.0.4-2 arm64 minimalistic Netlink communication library
ii rockchip-mali-midgard-dev 1.6-1 arm64 This package provides the development environment for compiling
ii rockchip-mali-midgard14 1.6-1 arm64 The ARM Mali™ library for Rockchip serial.
or pocl (from debian buster, the "experimental") version. I will try the "unstable" version of pocl and run JtR with and without Mali drivers.
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