Tuesday, May 1, 2007

Performance and Scalability Issues in .NET

Memory misuse. If you create too many objects, fail to properly release resources, preallocate memory, or explicitly force garbage collection, you can prevent the CLR from efficiently managing memory. This can lead to increased working set size and reduced performance.

Resource cleanup. Implementing finalizers when they are not needed, failing to suppress finalization in the Dispose method, or failing to release unmanaged resources can lead to unnecessary delays in reclaiming resources and can potentially create resource leaks.

Improper use of threads. Creating threads on a per-request basis and not sharing threads using thread pools can cause performance and scalability bottlenecks for server applications. The .NET Framework provides a self-tuning thread pool that should be used by server-side applications.

Abusing shared resources. Creating resources per request can lead to resource pressure, and failing to properly release shared resources can cause delays in reclaiming them. This quickly leads to scalability issues.

Type conversions. Implicit type conversions and mixing value and reference types leads to excessive boxing and unboxing operations. This impacts performance.

Misuse of collections. The .NET Framework class library provides an extensive set of collection types. Each collection type is designed to be used with specific storage and access requirements. Choosing the wrong type of collection for specific situations can impact performance.

Inefficient loops. Even the slightest coding inefficiency is magnified when that code is located inside a loop. Loops that access an object’s properties are a common culprit of performance bottlenecks, particularly if the object is remote or the property getter performs significant work.

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