Unnecessary dbus traffic due to constant VM stats updates

[qubesuser]

Qubes OS version:

R4.0-rc2

Steps to reproduce the behavior:

1. Run dbus-monitor and do nothing on the system

Expected behavior:

There should be no dbus traffic.

Actual behavior:

There is constant useless dbus traffic, mostly consisting of broadcasting updates of the "cpu_time" and "cpu_usage" properties for domains.

General notes:

This design is not ideal since it results in constant unnecessary wakeups and CPU usage.

Possible solutions:

1. Remove dbus broadcasting of stats updates. If something needs to know about domain stats, it should call admin.vm.Stats itself when it needs it
2. Activate the dbus broadcasting only while at least one application needs it. Use a separate dbus signal, so only apps that needs stats will be woken up, and not everyone who is listening for changes of persistent properties on domains. Fix all clients to not constantly listen for stats and instead enable and listen for stats only when needed (e.g. when the domain tray popup menu is open, for memory usage updates).

[marmarek]

As for the second point - currently there are only two applications listening for VM status changes, and one of them do need also stats. So, in practice the gain (of any solution here) would be minimal.
But indeed some better mechanism could be used, in future version.

[marmarek]

As for the second point - currently there are only two applications listening for VM status changes, and one of them do need also stats. So, in practice the gain (of any solution here) would be minimal.
But indeed some better mechanism could be used, in future version.

[qubesuser]

Assuming you are talking about the tray applets, they don't need stats when the menu isn't open.

[qubesuser]

Assuming you are talking about the tray applets, they don't need stats when the menu isn't open.