C# Dev #24: Parallel Programming - Use All Your CPU Cores with Parallel.For, ForEach & PLINQ
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Video Description
This is it - the final video in the C# for Beginners series! We're talking parallel programming: how to actually use all those CPU cores sitting in your machine. Parallel.For, Parallel.ForEach, and PLINQ. Let's make them work for their keep.
What you'll learn: • Parallel vs async - they solve different problems • Async = I/O waits, Parallel = CPU work • Parallel.For basics - transforming sequential loops • Parallel.ForEach - the collection-friendly version • ParallelOptions - controlling thread count • CancellationToken support in parallel operations • Thread safety is YOUR responsibility • Why regular collections aren't thread-safe • ConcurrentBag pattern for collecting results • PLINQ - just add .AsParallel() • WithDegreeOfParallelism, WithCancellation, AsOrdered • When PLINQ helps (and when it doesn't) • Real-world example: Image processing • Real-world example: Monte Carlo simulation • Local state pattern for high performance • Decision framework: ForEach vs For vs PLINQ vs Async
Key insights: • Async for I/O waits, Parallel for CPU work - don't confuse them • If the CPU isn't busy, parallel won't help • Each parallel iteration should be independent • Use ConcurrentBag, not List, for thread-safe results • PLINQ doesn't preserve order by default • Small datasets + simple operations = parallel overhead exceeds benefit • More cores = faster results (for CPU-bound work)
Common mistakes we'll avoid: • Using parallel for database/API calls (use async!) • Sharing mutable state between parallel iterations • Adding to collections from multiple threads • Using PLINQ on tiny datasets • Forgetting thread safety entirely
Previous Video: Async Best Practices ► Full Playlist: https://www.youtube.com/playlist?list=PLGxFXI4dC2shfDgudNdh1FtSLcAZG0-Ba ► Code Repository: https://github.com/benday-inc/csharp-for-beginners-2025
🎉 SERIES COMPLETE! Thanks for sticking with me through all 24 videos! If this series helped you, please like and subscribe - more content coming soon! What should I cover next? Let me know in the comments!
#CSharp #ParallelProgramming #PLINQ #DotNet #Programming #Threading #MultiCore #CodingTutorial #SeriesFinale
0:00 Parallel Programming 0:17 What We're Covering 0:33 Parallel vs Async: Not the Same Thing 1:17 When to Use Parallel 1:33 Parallel.For: The Basics 2:01 Parallel.ForEach: Collections Made Parallel 2:20 Controlling Parallelism 2:42 The Thread Safety Problem 3:10 Thread-Safe Pattern: Local Results 3:30 PLINQ: Parallel LINQ 3:55 PLINQ in Action 4:26 PLINQ Options 4:48 When PLINQ Helps (and When It Doesn't) 5:13 Real-World Example: Image Processing 5:40 Real-World Example: Monte Carlo Simulation 6:07 Choosing Your Approach 6:38 Series Wrap-Up 7:15 Thanks for Watching
Video Info
- Duration: 7:20
- Published: January 15, 2026
