I was surprised to find the Nvidia K1 to be a surprising departure from the ARM Cortex a53 and a57 cores.
Summary at: http://blogs.nvidia.com/blog/2014/08/11/tegra-k1-denver-64-bit-for-android/ Details at (if you are willing to share your email address): http://www.tiriasresearch.com/downloads/nvidia-charts-its-own-path-to-armv8/ Highlights: * The nvidia 64-bit denver core is in order! * dynamics code optimizer uses 128MB of ram to optimize frequently used code segments * Larger 128KB L1 I cache to handle microcode expansion * L1 I cache can deliver a 32 byte parcel to the scheduler every cycle * Optimizer is not visible to OS or hypervisor * 7 way issue * 13 cycle mispredict. * expected launch at 2.5 GHz * Slightly better than haswell celeron 2955U at SpecINT 2k * Slightly worse than haswell celeron 2955U at SpecFP 2k * new lower power state CC4 that allows maintaining cache and CPU state information that looks to be around 5mw from the graph. * special optimizations lookup table, 1k entries, jumps to the already optimized code. * 128MB cache does not contain any pre-canned optimizations for benchmarks. *chuckle* * Pin compatible with existing 32 bit K1 chips. The dynamics code optimization: * collects branch results (taken, not taken, strongly take, and strongly not taken). * performs register renaming * claimed comparable performance to OoO hardware implementations * claimed power efficiency of in order implementations * can reorder load/stores * remove redundant code * hoist redundant computations * unroll loops * claims larger instruction reorder window than hardware implementations Seems like the optimizer has a pretty tough job considering that compilers have already attempted similar optimizations with access to source code and relatively unlimited CPU/ram resources compared to a battery operated tablet/phone/widget. For reference, celeron 2955U = 2 cores @ 1.4GHz, 2MB cache, 15 watt TDP, haswell core, 25.6GB/sec mem bandwidth. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
