Streaming music from cloud storage

[simoncn]

(29-11-2023 21:19)GrumpyPatzer Wrote:  1. In both cases (command line test and MinimServer scan), it is typically taking between 200 and 350ms for each file operation, usually over 250ms but occasionally spiking to over 500ms. Unsurprisingly, the bulk of that time is that wait between the read(s) and the data being returned.

From this it appears that about 3 files per second is the most that can be achieved, even if only one read operation is needed for each file.

Quote:3. For each file, there are 16 individual read operations of 32kB each, so 512kB is being returned. (Based on what you say, it seems pretty likely that MinimServer is not asking for that much data. And the ‘head’ command only needs 32kB.)

Are the 16 reads just for a MinimServer scan or does this also happen for the 32 kB HEAD request?

Quote:So it seems that — for both the ten ‘head’ commands and the MinimServer scan — a minimum of 512kB is being obtained, even though this *may* be more than is being requested.

I do not know why this should be the case. It is, I suppose, possible that this is Mac OS file handling behaviour. The fact that 512kB is still being obtained when I reduce the rclone parameters to 64kB suggests (although not conclusively) that the 512kB is not as a result of rclone behaviour. Also, if we accept that 512kB is being requested, it seems plausible (and is consistent with what I am observing) that reducing the rclone read-chunk size to 64kB would slow things down — if that is causing there to be more round trips to OneDrive.

This seems to be the most likely explanation of what you are seeing.

Quote:It may simply be that the latency of opening and obtaining the first chunk of data from a file stored in OneDrive is typically going to average around 300ms, at best, irrespective of broadband speed (as it happens, our broadband service was upgraded from 150 to 500Mbps today).

My broadband connection is about 70 Mbps and I see latency of a few ms for simple network requests. This suggests the 300 ms latency you are seeing is almost all caused by OneDrive and increasing network bandwidth will make very little difference to the overall latency.

Quote:Unless I can think of (or you can suggest) something else to try, I’ll probably leave it there, at least for now. When I get time to set up my new Pi (which has just arrived), I’ll set it up with MinimServer and rclone and will try playing music stored in OneDrive over a longer period of time. I suppose it’s possible that, if the 512kB is indeed a Mac OS characteristic, we may observe different behaviour with Raspbian or Ubuntu on a Pi.

I will be interested to hear whether this changes what you are seeing.