Did you know you can measure time in .NET without allocating a new Stopwatch instance?
Starting with .NET 7, the Stopwatch class provides two static methods that let you track time without any allocations:
Stopwatch.GetTimestamp() – gets the current timestamp (a raw long value from a high-resolution timer)Stopwatch.GetElapsedTime(startTimestamp) – calculates the elapsed TimeSpan from a previously recorded timestampThis is a great way to avoid unnecessary allocations in high-performance or allocation-sensitive code.
Here’s how it works:
long start = Stopwatch.GetTimestamp();
// some work here...
await Task.Delay(150);
TimeSpan elapsed = Stopwatch.GetElapsedTime(start);
Console.WriteLine($"Elapsed time: {elapsed.TotalMilliseconds} ms");
// Elapsed time: ~150 ms
Unlike using a Stopwatch instance:
Stopwatch sw = Stopwatch.StartNew();
// allocates Stopwatch object
…this method avoids any object creation. You just work with raw long and TimeSpan values.
📑 Docs: System.Diagnostics.Stopwatch
Next time you measure execution time in a hot path, consider this allocation-free option!