Automobiles

1. Ronny Krashinsky Christopher Batten Krste Asanovic The Scale Vector-Thread Processor Embedded computing today… Smart phones Sensor Nets Robots Servers TVs Set-top Boxes Games Routers Laptops Automobiles Modern embedded systems All-purpose programmable core • Multiple programming languages and models • Multiple distinct memories • Multiple communication and synchronization models • Inflexible • Inefficient • Expensive SRAM SRAM CPU DSP1 DSP2 ChipSet FPGA • Handles all information processing • Unified software programming model • Competitive in performance and energy • Scale by tiling an efficient core DRAM ASIC DRAM

2. Vector-Thread Architecture vector-fetch Control Processor thread- fetch VP0 VP1 VP2 VP3 VPN Memory • VT unifies the vector and multithreaded compute models • A control processor interacts with a vector of virtual processors (VPs) • Vector-fetch: control processor fetches instruction blocks for all VPs in parallel • Thread-fetch: a VP fetches its own instruction blocks • VT allows a seamless intermixing of vector and thread control Vector Execution Threaded Execution VP3 VP3 Control Proc. VP1 VPN Control Proc. VP1 VPN VP2 VP2 VP0 VP0 vector-load vector-load vector-fetch vector-fetch vector-store vector-load vector-fetch vector-store vector-store

3. Control Processor (CP) – scalar RISC core • Vector-Thread Unit – 4 lanes, 16 decoupled clusters, instruction fetch, load/store, and command management units, up to 128 VP threads • Vector-Memory Unit – unit-stride, strided, and segment loads and stores, refill/access decoupling • Cache – 4-port, non-blocking, 32-way set-associative, 32 KB Lane 0 Lane 1 Lane 2 Lane 3 CMU CMU CMU CMU C3 C3 C3 C3 C2 C2 C2 C2 • Automatic synthesis, place & route • Preplaced standard cells, RAM blocks • Aggressive clock-gating • Iterative design flow • Verification: formal equiv. check + sim. Register File 32x32-bit Cache Tags Cache Control C1 C1 C1 C1 Instr. cache 32x46-bit Control Logic Datapath 32-bit C0 C0 C0 C0 • TSMC 180 nm, 6 layers Al • 7.1 M trans., 1.4 M gates, 397 K cells, 300 k RAM bits • 16.6 mm2 core area, 23.1 mm2 chip area • 260 MHz at 1.8 V, 600 mW typical • 24 person-months design effort SD SD SD SD CP Vector-Mem Unit Read/Write Crossbars • Vectorizable data processing applications, • e.g. 802.11a wireless transmitter: 9.7 ops per cycle • Non-vectorizable encoder/decoder algorithms, • e.g. ADPCM speech decompression: 6.5 ops per cycle • Threaded IP routing table lookups: 6.1 ops per cycle 32 KB SRAM 3mm