On Wed, Aug 28, 2019 at 5:17 PM Pavel Hofman pavhofman@gmail.com wrote:
IMO some common time frame must be used. E.g. kernel time in nanoseconds.
How about something like this:
- the core PCM part of alsa driver would keep relative samplerate and
present such value in proc/sysfs to userspace. the calculation something like: copied X sample frames in Y kernel nanosecs (for the last e.g. approx. 30 secs ), with nominal samplerate 48kHz. The value would be (10^9 * X frames/Y nanosecs) / 48000 Hz samplerate = e.g. 1.00001
Perhaps the relative throughput could be calculated in alsa-lib when talking to the driver? It has the same information available. Turned-on by some environment var, regular output to some /tmp file named after the corresponding hw card. Or does please alsa-lib have some existing debug output, similar to /proc/asound, apart of stderr?
I very much appreciate any comments. IMO this would be a very useful improvement, there are lots of RPi projects which would benefit from properly working USB-audio connectivity.
Thanks,
Pavel.