# Virtual-Threading: Advanced General Purpose Processors Architecture

## TL;DR

The paper introduces Virtual-Threading, a novel computer architecture designed to efficiently support general purpose parallel computing by virtualization of activities and high generalized latency tolerance.

## Contribution

It proposes the Virtual-Threaded Machine architecture, featuring activity virtualization, distributed register files, and hardware-driven synchronization, advancing parallel processing capabilities.

## Key findings

- Introduces the concept of Generalized Latency Tolerance (GLT).
- Describes the architecture supporting high GLT for GPPC.
- Proposes new OS programming styles free of interruptions.

## Abstract

The paper describes the new computers architecture, the main features of which has been claimed in the Russian Federation patent 2312388 and in the US patent application 11/991331. This architecture is intended to effective support of the General Purpose Parallel Computing (GPPC), the essence of which is extremely frequent switching of threads between states of activity and states of viewed in the paper the algorithmic latency. To emphasize the same impact of the architectural latency and the algorithmic latency upon GPPC, is introduced the new notion of the generalized latency and is defined its quantitative measure - the Generalized Latency Tolerance (GLT). It is shown that a well suited for GPPC implementation architecture should have high level of GLT and is described such architecture, which is called the Virtual-Threaded Machine. This architecture originates a processor virtualization in the direction of activities virtualization, which is orthogonal to the well-known direction of memory virtualization. The key elements of the architecture are 1) the distributed fine grain representation of the architectural register file, which elements are hardware swapped through levels of a microarchitectural memory, 2) the prioritized fine grain direct hardware multiprogramming, 3) the access controlled virtual addressing and 4) the hardware driven semaphores. The composition of these features lets to introduce new styles of operating system (OS) programming, which is free of interruptions, and of applied programming with a very rare using the OS services.