Delicious_Jaguar_341 shares a thoughtful discussion about advanced async/await usage in .NET, examining performance problems caused by the sync-over-async pattern and providing actionable tips for developers.

Async/Await - Beyond the Basics in .NET

Delicious_Jaguar_341 kicks off a community discussion centered on performance issues related to the sync-over-async pattern in .NET applications. The conversation draws on real-world debugging experiences and delves into the nuanced mistakes that are common among developers working with asynchronous code.

Key Points Covered

  • Sync-over-Async Problems: Real-world performance issues can arise from blocking asynchronous calls using patterns like DoSomethingAsync().Result and DoSomethingAsync().GetAwaiter().GetResult(). These techniques block threads and limit scalability, offering poor alternatives to proper async code execution.
  • Why It’s Frowned Upon: Both patterns introduce thread-blocking by turning asynchronous operations into synchronous ones, which can overwhelm thread pools and slow down I/O-bound applications.
  • Proper Practices: Developers are encouraged to refactor top-level code to be fully async when possible, rather than wrapping async calls in synchronous wrappers. This sometimes means overcoming API or GUI framework limitations.
  • Events and GUI Frameworks: Event handlers in GUI frameworks often require special handling since they natively support only synchronous operations. The discussion highlights why async void is typically discouraged, but sometimes necessary for event handlers, and advises on mitigation strategies.
  • Further Resources: The thread references a detailed Medium article for in-depth explanations and code samples: Do you really understand async/await?
  • Community Feedback and Insights: Participants share observations about the ‘viral’ nature of async, attempts to shortcut learning, and the need for deep understanding to write effective asynchronous .NET code.

Example Code Snippets

// Bad Practices
var result = DoSomethingAsync().Result;
var result = DoSomethingAsync().GetAwaiter().GetResult();

// Preferred Approach
async Task DoWorkAsync() {
    var result = await DoSomethingAsync();
    // Handle result
}

Additional Observations

  • Many developers internalize syntax but miss the underlying mechanics (e.g., state machine transformation, thread usage).
  • Misapplication of async/await, especially when integrating with legacy synchronous APIs or certain UI components, is extremely common.
  • Deep dives into .NET’s ThreadPool and differentiation between worker and IOCP threads are teased for future discussions.

Takeaways

Developers should resist ‘making async code synchronous,’ understand when and why to use async void, and strive to propagate async through their application layers. Community discussion and educational resources like this help bridge knowledge gaps and improve code quality.

For more insights, refer to the original Medium article and join the conversation for feedback and follow-ups.

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