TimestampedFileLogger is eating a lot of CPU

dotnet sdk 6.0.100-rc.1.21458.32

I have a case where a test is getting stuck (I believe this is unrelated to the SDK). However, while waiting for it, the parent dotnet.exe process is using a full CPU core.

Digging further, it seems like there is a tight loop in TimestampedFileLogger:

        private void WriteLog(object flushThreshold)
        {
            int writeCount = 0;
            int threshold = (int)flushThreshold;

            while (!Done)
            {
                if (_messageQueue.TryDequeue(out string message))
                {
                    _stream.WriteLine($"{TimeStamp} {message}");
                    writeCount = (writeCount + 1) % threshold;

                    if (writeCount == 0)
                    {
                        _stream.Flush();
                    }
                }
            }

Because of that, it will keep using a full core until the test run is finished. I believe some synchronization around the queue would be needed here (just switching to a BlockingCollection would help a lot).

[kevingosse]

Is this causing #21028 too?

I see the TimestampedFileLogger flush thread in your memory dump, so that seems very likely.

[marcpopMSFT]

PR got merged so closing.