• Source: Manycore processor

Manycore processors are special kinds of multi-core processors designed for a high degree of parallel processing, containing numerous simpler, independent processor cores (from a few tens of cores to thousands or more). Manycore processors are used extensively in embedded computers and high-performance computing.




Contrast with multicore architecture



Manycore processors are distinct from multi-core processors in being optimized from the outset for a higher degree of explicit parallelism, and for higher throughput (or lower power consumption) at the expense of latency and lower single-thread performance.
The broader category of multi-core processors, by contrast, are usually designed to efficiently run both parallel and serial code, and therefore place more emphasis on high single-thread performance (e.g. devoting more silicon to out-of-order execution, deeper pipelines, more superscalar execution units, and larger, more general caches), and shared memory. These techniques devote runtime resources toward figuring out implicit parallelism in a single thread. They are used in systems where they have evolved continuously (with backward compatibility) from single core processors. They usually have a 'few' cores (e.g. 2, 4, 8) and may be complemented by a manycore accelerator (such as a GPU) in a heterogeneous system.




Motivation


Cache coherency is an issue limiting the scaling of multicore processors. Manycore processors may bypass this with methods such as message passing, scratchpad memory, DMA, partitioned global address space, or read-only/non-coherent caches. A manycore processor using a network on a chip and local memories gives software the opportunity to explicitly optimise the spatial layout of tasks (e.g. as seen in tooling developed for TrueNorth).
Manycore processors may have more in common (conceptually) with technologies originating in high-performance computing such as clusters and vector processors.
GPUs may be considered a form of manycore processor having multiple shader processing units, and only being suitable for highly parallel code (high throughput, but extremely poor single thread performance).




Suitable programming models


Message passing interface
OpenCL or other APIs supporting compute kernels
Partitioned global address space
Actor model
OpenMP
Dataflow




Classes of manycore systems


GPUs, which can be described as manycore vector processors
Massively parallel processor array
Asynchronous array of simple processors




Specific manycore architectures


ZettaScaler [1], Japanese PEZY Computing 2,048-core modules
Xeon Phi coprocessor, which has MIC (Many Integrated Cores) architecture
Tilera
Adapteva Epiphany Architecture, a manycore chip using PGAS scratchpad memory
Coherent Logix hx3100 Processor, a 100-core DSP/GPP processor based on HyperX Architecture
Movidius Myriad 2, a manycore vision processing unit (VPU)
Kalray, a manycore PCI-e accelerator for data-intensive tasks
Teraflops Research Chip, a manycore processor using message passing
TrueNorth, an AI accelerator with a manycore network on a chip architecture
Green arrays, a manycore processor using message passing aimed at low power applications
Sunway SW26010, a 260-core manycore processor used in the then top 1 supercomputer Sunway TaihuLight
SW52020, an improved 520-core variant of SW26010, with 512-bit SIMD (also adding support for half-precision), used in a prototype, meant for an exascale system (and in the future 10 exascale system), and according to datacenterdynamics China is rumored to already have two separate exascale systems secretly
Eyeriss, a manycore processor designed for running convolutional neural nets for embedded vision applications
Graphcore, a manycore AI accelerator




Specific manycore computers with 1M+ CPU cores


A number of computers built from multicore processors have one million or more individual CPU cores. Examples include:

Gyoukou (Japanese: 暁光 Hepburn: gyōkō, dawn light), a supercomputer developed by ExaScaler and PEZY Computing, with 20,480,000 processing elements total plus the 1,250 Intel Xeon D host processors.
SpiNNaker, a massively parallel (1 million CPU cores) manycore processor (ARM-based) built as part of the Human Brain Project.




Specific computers with 5 million or more CPU cores


Quite a few supercomputers have over 5 million CPU cores. When there are also coprocessors, e.g. GPUs used with, then those cores are not listed in the core-count, then quite a few more computers would hit those targets.

Frontier
Fugaku, a Japanese supercomputer using Fujitsu A64FX ARM-based cores, 7,630,848 in total.
Sunway TaihuLight, a massively parallel (10 million CPU cores) Chinese supercomputer, once one of the fastest supercomputers in the world, using a custom manycore architecture. As of November 2018, it was the world's third fastest supercomputer (as ranked by the TOP500 list), obtaining its performance from 40,960 SW26010 manycore processors, each containing 256 cores.




See also


Multi-core processor
Vector processor
SIMD
High-performance computing
Computer cluster
Multiprocessor system on a chip
Vision processing unit
Memory access pattern
Cache coherency
Embarrassingly parallel
Massively parallel
CUDA




References






External links


Architecting solutions for the Manycore future, published on Feb 19, 2010 (more than one dead link in the slide)
Eyeriss architecture

Kata Kunci Pencarian:

• Manycore processor
• Massively parallel
• Multi-core processor
• Graphics processing unit
• Embarrassingly parallel
• Parallel computing
• Vision processing unit
• Sunway TaihuLight
• Massively parallel processor array
• Kalray