Performance

This page documents the performance optimizations employed by NamedSignal.

Optimizations

Linked Lists for O(1) Disconnect

Connections use doubly linked lists to maintain order while allowing constant-time disconnections.

While they are slower to iterate than an array, they avoid the extremely expensive shifting required by arrays when disconnecting.

Multi Thread Recycling

Every thread created for invocation is reused whenever possible, this cuts down on the overhead for spawning new threads.

Dual Layer Thread Cache

Inspired by CPU cache architecture, NamedSignal implements 2 layers of thread caching, a "fast" L1 cache (a local variable), and a "slow" thread pool (an array).

Accessing an upvalue is faster than indexing an array, so performance is slightly improved for non-yielding invocation.

Minimized Thread Resumption for Non-Yielding Connections

Most signal libraries cache one or more threads, however there is still a very large overhead for resumption.

NamedSignal improves upon this by using a more efficient dispatching technique that only resumes more threads when a callback yields, leading to vastly better non-yielding fire performance.

Avoiding The OOP API Internally

When a function that is part of the OOP interface is depended on internally, it's instead defined as a const function, which skips the __index lookup and allows the Luau compiler to perform function inling.

Benchmarks

Benchmarks are a work in progress!

For now testing uses Gohan's Certification's Speed Certification:

⚪ | Speed Certification     |  -  Server - Signal_Certifications:2023
--------------------------------------------------------------------------------------  -  Server - Signal_Certifications:1968
☑ | Create         | -0.6μs  | Baseline: 0.6μs  ▶ {...} | Results: 0.1μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Connect        | -0.6μs  | Baseline: 0.8μs  ▶ {...} | Results: 0.2μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Once           | -0.4μs  | Baseline: 0.7μs  ▶ {...} | Results: 0.2μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Fire_None      | +0.0μs  | Baseline: 0.1μs  ▶ {...} | Results: 0.1μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Fire_One       | +0.6μs  | Baseline: 0.4μs  ▶ {...} | Results: 0.9μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Fire_Many      | -0.1μs  | Baseline: 0.1μs  ▶ {...} | Results: 0.0μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Fire_OneYield  | +0.5μs  | Baseline: 0.7μs  ▶ {...} | Results: 1.2μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Fire_ManyYield | +0.8μs  | Baseline: 0.2μs  ▶ {...} | Results: 0.9μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | Disconnect     | -0.1μs  | Baseline: 0.2μs  ▶ {...} | Results: 0.1μs  ▶ {...}  -  Server - Signal_Certifications:225
☑ | DisconnectAll  | -7.1μs  | Baseline: 8.2μs  ▶ {...} | Results: 1.1μs  ▶ {...}  -  Server - Signal_Certifications:225
--------------------------------------------------------------------------------------  -  Server - Signal_Certifications:1968
✅ | Speed Certified         |  -  Server - Signal_Certifications:125