Scheduler Fairness and Real-Time Performance: Golang vs Erlang

Overview

This repository contains a comparative analysis of the scheduling fairness and real-time performance between Golang and Erlang. The tests demonstrate that Golang's goroutine scheduler performs poorly - it's crude, unfair, and lacks good real-time characteristics. In contrast, Erlang's scheduler proves significantly superior in both fairness and real-time performance!

Experimental Conclusions

Based on our rigorous testing:

• Golang's scheduler exhibits 粗糙 (crude) implementation, demonstrating clear unfairness and poor real-time performance
• Erlang's scheduler outperforms Golang dramatically, showing excellent fairness and real-time characteristics

Test Methodology

The Core Principle

The essence of scheduler evaluation lies in testing whether concurrent processes/goroutines receive fair treatment even when some routines are consuming substantial CPU resources. Other routines should enjoy equal execution opportunities rather than being forced into delay or blocking.

Implementation Approach

We designed two identical functions (work1 and work2) in both languages, then launched multiple resource-intensive routines (work_busy) to compete for system resources.

Accounting for Performance Differences

While Golang (as a static language) naturally delivers higher performance, we adjusted the number of work_busy routines appropriately for each language to ensure:

• Both implementations maintain similar execution rates (approximately 60-80 executions per second)
• work1 and work2 achieve roughly the same execution counts within the same timeframe
• The comparison focuses specifically on scheduler behavior rather than raw language performance

Test Environment and Versions

The tests were conducted using the following runtime versions:

• Erlang/OTP: Version 27 [erts-15.0.1] [64-bit] [smp:16:16]
• Golang: version go1.25.0 windows/amd64

Platform Hardware & OS Environment:

• Device: LAPTOP-H670TST5
• Processor: 13th Gen Intel(R) Core(TM) i5-1340P (1.90 GHz)
• Memory: 16.0 GB RAM
• OS: Windows 11 Home Chinese Edition (24H2)
• OS Version: 26100.4946
• Architecture: 64-bit operating system, x64-based processor

Start to run golang:


Start to run Erlang:

Results Analysis

After running approximately 10,000 iterations:

• Golang results: work1 and work2 showed a difference of over 100 executions
• Erlang results: work1 and work2 differed by only 1 execution - an astonishing result!

Result of golang:

Result of erlang:

Key Insights

Erlang's scheduler demonstrates true soft real-time capabilities and implements genuinely fair preemptive scheduling - areas where Golang clearly falls short. The longer Golang runs under CPU-intensive conditions, the greater the disparity between work1 and work2 becomes.

Conclusion

This comparison reveals fundamental differences in scheduler design philosophy. Erlang's battle-tested process scheduler, designed for telecommunications-grade reliability, demonstrates superior fairness and real-time characteristics compared to Golang's more recent goroutine scheduler, particularly under sustained CPU pressure.