Logical thread

As explained in Learn Concurrent Programming with Go

A user-level thread is a thread managed by a language runtime or user-space library rather than directly by the operating system kernel.

A logical thread is a user-level thread: a unit of execution managed inside an application by a language runtime or user-space library rather than directly by the operating system. The operating system sees the containing process as having one kernel-level thread, while the runtime schedules and switches among its logical threads. section 2.3.2

Go models logical threads with goroutines. A goroutine is neither an operating-system process nor an OS thread; current Go implementations group goroutine executions onto OS threads and let the Go runtime manage their execution. section 2.3.2 section 1.5.1

A logical-thread design separates application-level concurrency from kernel-level scheduling:

• Keeps thread state, scheduling, and context switching in a runtime-managed table inside the process. section 2.3.2
• Lets a program create many goroutines without directly managing one operating-system thread for each concurrent task. section 1.5.1
• Relies on the runtime and hardware to determine how concurrent executions scale across available kernel-level threads. section 1.5.1

Figure 2.9 User-level threads executing within a single kernel-level thread

Shows logical threads executing within a single kernel-level thread, making the boundary between user-space execution and operating-system visibility concrete. section 2.3.2

How Learn Concurrent Programming with Go covers it

How deep it goes

Explains runtime scheduling, state management, and context switching, while noting that Go’s specification does not guarantee a specific implementation.

Examples

Uses a diagram of user-level threads inside one kernel-level thread and goroutines mapped onto kernel-level threads.

What it assumes

Assumes basic familiarity with processes and threads, while distinguishing kernel-level threads from user-level threads.

What you can do after

Understand how Go separates goroutine creation from operating-system thread management.

How it connects

Connects logical threads with goroutines, kernel-level threads, processes, the Go runtime, parallelism, and channels.

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Also explained in

• 

  liveBookmanning.com
  Functional Programming in Scala, Second EditionA logical thread is an independent line of computation used to describe concurrent execution without necessarily denoting a physical operating-system thread.
• 

  liveBookmanning.com
  Grokking ConcurrencyA user-level thread is a thread managed by a user-space runtime or library rather than directly by the operating system.

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Related concepts

• threadcontrasts with · A thread is an independently schedulable sequence or context of execution within a program or process.
• cooperative multitaskingused by · Cooperative multitasking is a scheduling technique in which executing tasks voluntarily yield control at defined points so other tasks can run.
• goroutineincludes · A goroutine is a lightweight function execution unit managed by the Go runtime that runs concurrently with other program activity.
• Go runtimeused by · The Go runtime is the execution support system for Go programs, providing services such as goroutine scheduling, memory management, and garbage collection.

This explainer was generated by Manning's knowledge graph from the text of Learn Concurrent Programming with Go. The section links point to the parts of the book it draws on.