Network Service Task Scheduler

This directory contains the implementation for an experimental task scheduler on Chromium's Network Service.

The scheduler introduces a base::sequence_manager::SequenceManager configured with multiple prioritized task queues. The primary goal is to allow high-priority network tasks (e.g., those critical for navigation) to execute with precedence over lower-priority tasks, aiming to improve user-perceived performance metrics like FCP and LCP.

Design

For a detailed explanation of the design, motivations, and implementation plan, please refer to the design document: go/task-scheduler-in-net (Google internal)

Overview

The core mechanism involves:

1. Initializing a SequenceManager on the Network Service Thread.
2. Creating at least two TaskQueues: one for high-priority tasks and one for default-priority tasks.
3. Exposing TaskRunners associated with these queues.
4. Modifying relevant PostTask call sites in //net and //services/network to route tasks to the appropriate TaskRunner based on the task's conceptual priority (often derived from net::RequestPriority).

Status

This feature is currently experimental and under development. Its impact is being evaluated via diagnostic metrics and Finch experiments.