Why are all my threads being momentarily paused?

PlatypusPotato 1

Hi, I've been struggling with this for weeks. I have several audio threads in my application (they all have high priorities in the 20's from the multimedia class scheduler service). They are often held up for long periods of time (100ms, 300ms, even longer). Naturally this causes audio dropouts. Here is a shot of one from Windows Performance Analyzer:

Thread 25216 is a thread where I sleep for 10ms and write a tone output to a WASAPI device, and that's all. Where I've circled, it has been suspended for about 170ms. It is not being pre-empted by higher priority threads (notice chrome.exe and the Idle thread are still running). In fact, my whole process seems to be suspended for most of this time, and other processes on the machine are fine.

Does anyone have any ideas? Thanks!

Rita Han - MSFT 2,161 Reputation points

2020-08-05T01:46:35.25+00:00

Welcome to Microsoft Q&A! How do you write a tone output to a WASAPI device? Maybe the thread is suspended in deeper code.
PlatypusPotato 1 Reputation point

2020-08-06T16:36:11.843+00:00

Hi, I mean I'm writing a test audio signal (a 1kHz tone) to a WASAPI render device, so that I can hear when the thread is stopped. Does that answer your question?
Rita Han - MSFT 2,161 Reputation points

2020-08-07T02:27:20.553+00:00
I mean what main APIs you used in the step of "write a tone output to a WASAPI device". 2. One possibility is Priority Inversion happens. That is low priority thread holds the resource that the thread 25216 is waiting for. 3. You can follow "Use MXA to Analyze Audio Glitches" to catch the CallStack.
PlatypusPotato 1 Reputation point

2020-08-14T18:40:09.047+00:00

Hi, your link to MXA doesn't work. I can't find anything about MXA after 2016.
Carl 1 Reputation point

2020-08-18T07:24:58.507+00:00

Latest Media experience analyser can be found inside Windows ADK.
https://learn.microsoft.com/en-us/windows-hardware/get-started/adk-install