VISC architecture

Last updated

In computing, VISC architecture (after Virtual Instruction Set Computing) is a processor instruction set architecture and microarchitecture developed by Soft Machines, [1] [2] [3] [4] which uses the Virtual Software Layer (translation layer) to dispatch a single thread of instructions to the Global Front End which splits instructions into virtual hardware threadlets which are then dispatched to separate virtual cores. These virtual cores can then send them to the available resources on any of the physical cores. Multiple virtual cores can push threadlets into the reorder buffer of a single physical core, which can split partial instructions and data from multiple threadlets through the execution ports at the same time. Each virtual core keeps track of the position of the relative output. This form of multithreading ( simultaneous multithreading ) can increase single threaded performance by allowing a single thread to use all resources of the CPU. The allocation of resources is dynamic on a near-single cycle latency level (1–4 cycles depending on the change in allocation depending on individual application needs. Therefore, if two virtual cores are competing for resources, there are appropriate algorithms in place to determine what resources are to be allocated where. Unlike the traditional processor designs, VISC doesn't use physical cores, instead the resources of the chip are made available as 'virtual cores' and 'virtual hardware threads' according to workload needs. [5]

Related Research Articles

<span class="mw-page-title-main">Central processing unit</span> Central computer component which executes instructions

A central processing unit (CPU), also called a central processor, main processor, or just processor, is the most important processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs).

<span class="mw-page-title-main">Process (computing)</span> Particular execution of a computer program

In computing, a process is the instance of a computer program that is being executed by one or many threads. There are many different process models, some of which are light weight, but almost all processes are rooted in an operating system (OS) process which comprises the program code, assigned system resources, physical and logical access permissions, and data structures to initiate, control and coordinate execution activity. Depending on the OS, a process may be made up of multiple threads of execution that execute instructions concurrently.

<span class="mw-page-title-main">Thread (computing)</span> Smallest sequence of programmed instructions that can be managed independently by a scheduler

In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. In many cases, a thread is a component of a process.

<span class="mw-page-title-main">Superscalar processor</span> CPU that implements instruction-level parallelism within a single processor

A superscalar processor is a CPU that implements a form of parallelism called instruction-level parallelism within a single processor. In contrast to a scalar processor, which can execute at most one single instruction per clock cycle, a superscalar processor can execute more than one instruction during a clock cycle by simultaneously dispatching multiple instructions to different execution units on the processor. It therefore allows more throughput than would otherwise be possible at a given clock rate. Each execution unit is not a separate processor, but an execution resource within a single CPU such as an arithmetic logic unit.

Very long instruction word (VLIW) refers to instruction set architectures that are designed to exploit instruction-level parallelism (ILP). A VLIW processor allows programs to explicitly specify instructions to execute in parallel, whereas conventional central processing units (CPUs) mostly allow programs to specify instructions to execute in sequence only. VLIW is intended to allow higher performance without the complexity inherent in some other designs.

<span class="mw-page-title-main">Parallel computing</span> Programming paradigm in which many processes are executed simultaneously

Parallel computing is a type of computation in which many calculations or processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. There are several different forms of parallel computing: bit-level, instruction-level, data, and task parallelism. Parallelism has long been employed in high-performance computing, but has gained broader interest due to the physical constraints preventing frequency scaling. As power consumption by computers has become a concern in recent years, parallel computing has become the dominant paradigm in computer architecture, mainly in the form of multi-core processors.

<span class="mw-page-title-main">Hyper-threading</span> Proprietary simultaneous multithreading implementation by Intel

Hyper-threading is Intel's proprietary simultaneous multithreading (SMT) implementation used to improve parallelization of computations performed on x86 microprocessors. It was introduced on Xeon server processors in February 2002 and on Pentium 4 desktop processors in November 2002. Since then, Intel has included this technology in Itanium, Atom, and Core 'i' Series CPUs, among others.

Simultaneous multithreading (SMT) is a technique for improving the overall efficiency of superscalar CPUs with hardware multithreading. SMT permits multiple independent threads of execution to better use the resources provided by modern processor architectures.

A barrel processor is a CPU that switches between threads of execution on every cycle. This CPU design technique is also known as "interleaved" or "fine-grained" temporal multithreading. Unlike simultaneous multithreading in modern superscalar architectures, it generally does not allow execution of multiple instructions in one cycle.

<span class="mw-page-title-main">Microarchitecture</span> Component of computer engineering

In electronics, computer science and computer engineering, microarchitecture, also called computer organization and sometimes abbreviated as μarch or uarch, is the way a given instruction set architecture (ISA) is implemented in a particular processor. A given ISA may be implemented with different microarchitectures; implementations may vary due to different goals of a given design or due to shifts in technology.

<span class="mw-page-title-main">Hardware acceleration</span> Specialized computer hardware

Hardware acceleration is the use of computer hardware designed to perform specific functions more efficiently when compared to software running on a general-purpose central processing unit (CPU). Any transformation of data that can be calculated in software running on a generic CPU can also be calculated in custom-made hardware, or in some mix of both.

<span class="mw-page-title-main">Multi-core processor</span> Microprocessor with more than one processing unit

A multi-core processor (MCP) is a microprocessor on a single integrated circuit (IC) with two or more separate central processing units (CPUs), called cores to emphasize their multiplicity. Each core reads and executes program instructions, specifically ordinary CPU instructions. However, the MCP can run instructions on separate cores at the same time, increasing overall speed for programs that support multithreading or other parallel computing techniques. Manufacturers typically integrate the cores onto a single IC die, known as a chip multiprocessor (CMP), or onto multiple dies in a single chip package. As of 2024, the microprocessors used in almost all new personal computers are multi-core.

<span class="mw-page-title-main">Multithreading (computer architecture)</span> Ability of a CPU to provide multiple threads of execution concurrently

In computer architecture, multithreading is the ability of a central processing unit (CPU) to provide multiple threads of execution.

The AMD Bulldozer Family 15h is a microprocessor microarchitecture for the FX and Opteron line of processors, developed by AMD for the desktop and server markets. Bulldozer is the codename for this family of microarchitectures. It was released on October 12, 2011, as the successor to the K10 microarchitecture.

<span class="mw-page-title-main">Computer architecture</span> Set of rules describing computer system

In computer science and computer engineering, computer architecture is a description of the structure of a computer system made from component parts. It can sometimes be a high-level description that ignores details of the implementation. At a more detailed level, the description may include the instruction set architecture design, microarchitecture design, logic design, and implementation.

<span class="mw-page-title-main">POWER8</span> 2014 family of multi-core microprocessors by IBM

POWER8 is a family of superscalar multi-core microprocessors based on the Power ISA, announced in August 2013 at the Hot Chips conference. The designs are available for licensing under the OpenPOWER Foundation, which is the first time for such availability of IBM's highest-end processors.

<span class="mw-page-title-main">SPARC T4</span>

The SPARC T4 is a SPARC multicore microprocessor introduced in 2011 by Oracle Corporation. The processor is designed to offer high multithreaded performance, as well as high single threaded performance from the same chip. The chip is the 4th generation processor in the T-Series family. Sun Microsystems brought the first T-Series processor to market in 2005.

Hexagon is the brand name for a family of digital signal processor (DSP) and later neural processing unit (NPU) products by Qualcomm. Hexagon is also known as QDSP6, standing for “sixth generation digital signal processor.” According to Qualcomm, the Hexagon architecture is designed to deliver performance with low power over a variety of applications.

<span class="mw-page-title-main">Zen (first generation)</span> 2017 AMD 14-nanometer processor microarchitecture

Zen is the first iteration in the Zen family of computer processor microarchitectures from AMD. It was first used with their Ryzen series of CPUs in February 2017. The first Zen-based preview system was demonstrated at E3 2016, and first substantially detailed at an event hosted a block away from the Intel Developer Forum 2016. The first Zen-based CPUs, codenamed "Summit Ridge", reached the market in early March 2017, Zen-derived Epyc server processors launched in June 2017 and Zen-based APUs arrived in November 2017.

Sunny Cove is a codename for a CPU microarchitecture developed by Intel, first released in September 2019. It succeeds the Palm Cove microarchitecture and is fabricated using Intel's 10 nm process node. The microarchitecture is implemented in 10th-generation Intel Core processors for mobile and third generation Xeon scalable server processors. 10th-generation Intel Core mobile processors were released in September 2019, while the Xeon server processors were released on April 6, 2021.

References

  1. Cutress, Ian (12 February 2016). "Examining Soft Machines' Architecture: An Element of VISC to Improving IPC". AnandTech.
  2. "Next Gen Processor Performance Revealed". VR World. February 4, 2016. Archived from the original on 2017-01-13.
  3. "Architectural Waves". Soft Machines. 2017. Archived from the original on 2017-03-29.
  4. "Examining Soft Machines' Architecture: An Element of VISC to Improving IPC - Cheap PC hardware News & Rumors".
  5. "Soft Machines unveils VISC virtual chip architecture | bit-tech.net".