Date: Sun, 15 Sep 2013 06:06:32 +0400 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: GTX TITAN (was: new dev box wishes) On Wed, Jun 26, 2013 at 02:56:44PM +0400, Solar Designer wrote: > http://www.xbitlabs.com/articles/graphics/display/zotac-geforce-gtx-titan-amp-edition-6gb-sli.html#sect0 > > Stock clocks: > 837 MHz base, 876 MHz boost, 6008 MHz memory > Vendor o/c: > 902 MHz base, 954 MHz boost, 6608 MHz memory I just ran the FlopsCL_src_linux.zip benchmark from here http://olab.is.s.u-tokyo.ac.jp/~kamil.rocki/projects.html on our TITAN. It is in fact faster than stock TITAN, exceeding its peak GFLOPS at single-precision (should be 4500 GFLOPS for stock, we get 5000+ peak). However, as I was afraid, its double-precision performance is currently locked, which per some forum comments is unlock-able to full via nvidia-settings (need to add this GPU to xorg.conf first for that). Unfortunately, as expected, "nvidia-smi --gom=..." refused to work on this GPU (most nvidia-smi features work on TESLA cards only). [float ] Time: 0.085911s, 3199.58 GFLOP/s [float2 ] Time: 0.156523s, 3512.29 GFLOP/s [float4 ] Time: 0.219421s, 5010.96 GFLOP/s [float8 ] Time: 0.472510s, 4653.92 GFLOP/s [float16 ] Time: 0.885512s, 4966.67 GFLOP/s [double ] Time: 1.176065s, 233.73 GFLOP/s [double2 ] Time: 2.352377s, 233.70 GFLOP/s [double4 ] Time: 4.700395s, 233.92 GFLOP/s [double8 ] Time: 9.401957s, 233.89 GFLOP/s ERROR: clEnqueueNDRangeKernel failed, cl_out_of_resources [double16] Time: 0.016776s, 262160.00 GFLOP/s I don't know why double16 fails. FlopsCUDA_src_linux.zip, after teaching it about compute capability 3.5 corresponding to 192 SPs/MP (added one line to the table), gives: ----- Standard benchmark, sequential instructions are dependent ------------- [Device 0, GeForce GTX TITAN] Time: 0.042523 (s), Total FLOPs : 134217728000 [Device 0, GeForce GTX TITAN] Peak GFLOP/s: 5128.70, Actual GFLOP/s: 3156.4, 61.543% efficiency ----- Instruction-level parallelism (ILP): multiple independent instructions (i.e. used by Kepler's warp scheduler) ---- [Device 0, GeForce GTX TITAN] (ILP) Time: 0.122247 (s), Total FLOPs : 536870912000 [Device 0, GeForce GTX TITAN] (ILP) Peak GFLOP/s: 5128.70, Actual GFLOP/s: 4391.7, 85.630% efficiency The "Peak GFLOP/s" it calculates from querying the device for MP count, compute capability, and max boost clock rate (it gets 954 MHz here). I guess these results may teach us something about optimization for this GPU (and other Kepler GPUs?) - four-element vectors or(/and?) interleaving of independent instructions give best results. As to double-precision performance, indeed it does not matter for JtR (at least currently), yet it may be relevant if we let other projects use our dev boxes as well. Alexander
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