implementing Concurrent Dictionary Access in C# 10 - Performance Bottlenecks and Deadlocks
I'm migrating some code and I'm working on a personal project and This might be a silly question, but I've been banging my head against this for hours... I'm working with performance optimization when accessing a `ConcurrentDictionary<TKey, TValue>` in C# 10. The application is multithreaded, and while I expect the concurrent dictionary to handle simultaneous reads and writes efficiently, I'm working with important bottlenecks and, occasionally, deadlocks. Specifically, the problematic code section involves multiple threads trying to add or update values concurrently. Here's a simplified version of the code: ```csharp var concurrentDict = new ConcurrentDictionary<int, string>(); Parallel.For(0, 1000, i => { // Simulating some condition that requires checking the existence and then adding a value if (!concurrentDict.ContainsKey(i)) { concurrentDict.TryAdd(i, "Value " + i); } }); ``` I've verified that the dictionary is indeed being accessed in parallel, yet I notice that the overall execution time does not scale linearly with the number of threads. Additionally, if I include a log statement inside the loop to track the progress, it seems to slow down even further, suggesting that context switching might be an scenario. I've also tried using `GetOrAdd` to simplify the add logic: ```csharp Parallel.For(0, 1000, i => { concurrentDict.GetOrAdd(i, "Value " + i); }); ``` However, the performance is still not meeting expectations. I receive occasional timeouts or deadlocks, especially when the load increases. Is there a better approach to manage concurrent access in a way that enhances performance? Should I be considering different data structures for this use case? Any guidance on best practices for optimizing `ConcurrentDictionary` operations in a high-load scenario would be appreciated. Am I missing something obvious? Any ideas what could be causing this? Thanks in advance! This is for a web app running on CentOS. The stack includes C# and several other technologies. Am I approaching this the right way?