Hot Chips 2018: NEC Vector Processor Live Blog

08:59PM EDT - We saw this at Supercomputing last year: NEC's new Vector PCIe co-processor. I've wanted to write about it for a while, so I'm glad it's being presented here at Hot Chips. The talk is set to start at 6pm PT / 1am UTC.

09:00PM EDT - SX-Aurora TSUBASA

09:00PM EDT - NEC is a vector processor supercomputer

09:01PM EDT - based company

09:01PM EDT - SX-ACE in 2013 was 28 nm, 1.0 GHz, 256 GFLOPs, 256GB/sec per processor

09:01PM EDT - Do a lot of compiler work

09:02PM EDT - Vector computing for HPC

09:02PM EDT - Focused on large scale supercomputer before, so developed new supercomputer with a vector technology based on the engine

09:03PM EDT - Each node is x86 CPU + Vector Engine with high memory bandwidth and flexible configuration

09:03PM EDT - x86 and Linux, Fortran/C/C++

09:03PM EDT - Automatic vectorization and parallelization by proven vector compiler

09:04PM EDT - Vector Engine is TRANSPARENT to code

09:05PM EDT - Scales from Desktop Tower up to supercomputer

09:05PM EDT - Air cooled and liquid cooled cards

09:06PM EDT - Only one 8-pin connector

09:06PM EDT - PCIe 3.0 x16

09:06PM EDT - Dual slot, sub-300W

09:06PM EDT - only one 8-pin and 300W?

09:07PM EDT - 6 x HBM2

09:07PM EDT - TSMC and Broadcom assist

09:07PM EDT - 1.2 TB/s bandwidth

09:08PM EDT - 2.5D Interposer

09:08PM EDT - VE processor is 15x33mm

09:09PM EDT - 16MB LCC, 2D Mesh

09:09PM EDT - 1.6 GHz, 4.95 TFLOP single precision

09:09PM EDT - Up to 48GB HBM2

09:09PM EDT - 16nm FF

09:09PM EDT - 307GF in DP per core

09:09PM EDT - 8 vector cores inside

09:10PM EDT - Vector processing unit and scalar processing unit

09:10PM EDT - Scalar Processing Unit provides basic functionality - fetch, decode, branch, add, exceptions

09:10PM EDT - Controls the status of the core

09:11PM EDT - Address translation and data forwarding crossbar

09:11PM EDT - 16 elements/cycle vector address generation and translation, 17 requests/cycle issuing

09:11PM EDT - 409.6 GB/sec load and store data forwwarding

09:12PM EDT - Four pipelines, each 32-way parallel

09:12PM EDT - Total 96 FMAs per core

09:12PM EDT - Doubled SP perf by 32-bit x 2 packed vector data

09:12PM EDT - Vector register renaming with 256 physical VRs

09:13PM EDT - 7 VR banks per Vector Pipeline

09:13PM EDT - 32 VPPs per core

09:13PM EDT - OoO scheduling

09:13PM EDT - Dedicated complex operation pipeline

09:14PM EDT - Scalar part of core is traditional front end

09:14PM EDT - 4 instruction fetch and decode

09:14PM EDT - branch predictor

09:14PM EDT - 8-level speculative execution

09:15PM EDT - 32kB L1 cache and unified 256kb L2

09:15PM EDT - hardware prefetch

09:15PM EDT - Support for contiguous vector instruction pipes

09:16PM EDT - Memory subsystem to support 3 TB/s LLC bandwidth

09:16PM EDT - 1.2 TB HBM2 bandwidth

09:16PM EDT - Scalar L1/L2 ineach core

09:16PM EDT - 2 memory networks - 2D Mesh NoC for cores, also ring bus for DMA

09:16PM EDT - DMA engine used by vector cores and x86 node

09:17PM EDT - DMA engine can be virtualized

09:17PM EDT - Can access VE Memory, VE Registers, and x86 memory

09:17PM EDT - mapped through PCIe

09:17PM EDT - 2D mesh maximuses bandwith with minimal wiring

09:17PM EDT - 16 layer mesh

09:18PM EDT - Age based QoS control

09:18PM EDT - Dimension ordered routing

09:19PM EDT - L3 is 16MB write back

09:19PM EDT - Inclusive of L1 and L2

09:19PM EDT - 128 banks, auto data scrubbing

09:19PM EDT - assignable data buffer feature

09:20PM EDT - Vector Engine is much cheaper than V100

09:21PM EDT - Design target for VE not best Perf/Watt, but beat Xeon. Not optimized yet

09:22PM EDT - Performance on machine learning up to 107x over Xeon

09:23PM EDT - Very competitive with GPGPU using standard programming paradigms

09:23PM EDT - Q&A;

09:31PM EDT - Sorry, left to ask a question about power. That's a wrap, hope you enjoyed our Hot Chips coverage!