Real-time Playback Slowdown with Multiple Stacked Plots, Throttle Rate 100

[altsv]

Hello,

When running multiple stacked plots in real-time playback on the openmct-quickstart docker container with throttleRate set to 100 in the config, we run into the following issue:

https://streamable.com/6l41as

At around 5 minutes, the interface begins to lag and the real-time clock ticks slow down.
Is there a way to prevent this slowdown? Or does Open MCT not support real-time playback of this many telemetry sources at this speed? We recorded this with the memory tab open in DevTools for your reference. Please let me know if I should provide any more information!

Thank you so much,
Simon

[ozyx]

Hi Simon! Thanks for reporting this. The video was very helpful, so thanks for that as well.

We have some changes related to telemetry batching and throttling coming in openmct-yamcs 4.0.0 that should directly address this issue. @akhenry can speak to this in a bit more detail.

When running multiple stacked plots in real-time playback on the openmct-quickstart docker container with throttleRate set to 100 in the config

By this do you mean you're altering the simulator script to send telemetry at 100Hz?

[altsv]

Hi @ozyx ,

Thank you so much for taking the time to respond!
We set the throttleRate to 100ms in the openmct-quickstart's config like so in openmct-quickstart.js to match the 10hz rate being generated by the simulator:

const installYamcsPlugin = window.openmctYamcs;

const config = {
    "yamcsDictionaryEndpoint": "http://localhost:8040/yamcs/",
    "yamcsHistoricalEndpoint": "http://localhost:8040/yamcs/",
    "yamcsWebsocketEndpoint": "ws://localhost:8040/yamcs/api/websocket",
    "yamcsUserEndpoint": "http://localhost:8040/yamcs/api/user/",
    "yamcsInstance": "myproject",
    "yamcsFolder": "myproject",
    "throttleRate": 100
};

[altsv]

@ozyx @akhenry
Hello, we tried out the most recent openmct-yamcs 4.0.0-next version, and there has been a visible improvement in performance due to the new batching changes which is great!

A video of the improved performance with 3 stacked plots can be found here: https://streamable.com/rnf2gh

When we add one more stacked plot, however, it starts lagging and dropping multiple telemetry points: https://streamable.com/gdhxu3

This is with a 10hz throttle rate (throttleRate set to 100) with a batch size of 20. The console logs are shown for your reference.

Is there something on our end we can do to improve performance? Or does Open MCT not support playback for this many sources at a 10hz speed? Please let me know if you need any more info. Thank you!