F24 → F25 upgrade made my system sluggish (input lag?)

[Martin Ueding]

I have upgraded my Fedora installation from 24 to 25. Since then, things
that were done instantly before *sometimes* take half a second now.
Examples are:

- Switching the workspace in Awesome WM
- Typing something into the terminal (Konsole, fish shell)
- Pasting with the mousewheel (e.g. into Freemind, a Java Mindmap
  software)
- Starting a new terminal window
- Performing an action in Firefox

I do not quite know where this is coming from. Since it impacts a lot of
programs from various toolkits (Qt, GTK, Java), I am not really sure
what is going on. This regression is not catastrophic but rather
annoying.

When I try to select some text with the mouse, the mouse button
sometimes get “stuck” and it selects much more text than I wanted.
Overal this feels like a massive input lag at times.

My display manager is LightDM, I use Awesome WM and a bunch of KDE
programs. `htop` does not show anything out of the ordinary. The idle
load is at around 2%

How could I diagnose this regressions? There are no issues in
`journalctl -f` whenever there is a short lag. Any log that might help?

---

I have posted this [here](http://unix.stackexchange.com/q/328479/8251)
already but did not get any helpful feedback. That is why I now ask
here.

[Thomas Daede]

On 12/14/2016 03:29 AM, Martin Ueding wrote:
>  How could I diagnose this regressions? There are no issues in
>  `journalctl -f` whenever there is a short lag. Any log that might help? 
Could it be something to do with dbus? Do all of these actions make
messages appear in dbus-monitor? I've noticed a similar lag, but only
when opening links in a Firefox window.

[Martin Ueding]

Am 14.12.2016 um 21:38 schrieb Thomas Daede:
>  Could it be something to do with dbus? Do all of these actions make
>  messages appear in dbus-monitor? 
I have checked that the dbus-monitor for a couple of days now, there are
a couple bursts but not exactly when there is a lag. At least there are
lags where there are no bursts.