Is Stopwatch.ElapsedTicks threadsafe?

Question

If I have a shared System.Diagnostics.Stopwatch instance, can multiple threads call shared.ElapsedTicks in a safe manner and get accurate results?<

Answer 1

Looking at the source code, it is thread-safe, but you must not use: Stop(), Reset() and Restart().

So, if you start a shared instance, does not modify it and call only ElapsedXXX properties, you should be fine.

Answer 2

From MSDN:

Any instance members are not guaranteed to be thread safe.

Answer 3

Looking at the source code, it is not thread-safe.

Answer 4

You can use https://msdn.microsoft.com/en-us/library/dd642243(v=vs.110).aspx

ThreadLocal<T> 

like this:

    ThreadLocal<Random> _localRandom = new ThreadLocal<Random>(() => new Random());
    ThreadLocal<Stopwatch> _localStopwatch = new ThreadLocal<Stopwatch>(() => new Stopwatch());

    public void SomeTest()
    {
        Action someAction = () =>
            {
                _localStopwatch.Value.Reset();
                _localStopwatch.Value.Start();
                Thread.Sleep(_localRandom.Value.Next(100, 500));
                _localStopwatch.Value.Stop();
                Debug.Print(_localStopwatch.Value.Elapsed.TotalMilliseconds.ToString(CultureInfo.InvariantCulture));
            };

        var actions = Enumerable.Range(0, 1000).Select(i => someAction).ToArray();
        Parallel.Invoke(new ParallelOptions {MaxDegreeOfParallelism = Environment.ProcessorCount}, actions);
    }