Bug 238578

Summary:	[GTK] WebKitGTK3's compositing has extremely slow typing performance on Intel Sandybridge graphics with multiple screens/monitors and makes Evolution's HTML mail composer unusable
Product:	WebKit	Reporter:	Jeff Fortin <nekohayo>
Component:	WebKitGTK	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Major	CC:	bugs-noreply, cgarcia, mcatanzaro
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	PC
OS:	Linux
See Also:	https://bugzilla.redhat.com/show_bug.cgi?id=2068855
Bug Depends on:
Bug Blocks:	245783

Description Jeff Fortin 2022-03-30 15:34:02 PDT

Originally filed at https://bugzilla.redhat.com/show_bug.cgi?id=2068855

Unaffected versions I tested:

webkit2gtk3-2.34.0-1.fc35.x86_64
webkit2gtk3-jsc-2.34.0-1.fc35.x86_64

Affected versions I tested:

webkit2gtk3-2.36.0-2.fc35.x86_64
webkit2gtk3-jsc-2.36.0-2.fc35.x86_64


# Symptoms

On a fresh boot, on a ThinkPad X220 (Intel Sandybridge graphics) on GNOME's Xorg/X11 session, with a dual-monitor setup, with the affected versions of webkit2gtk3 mentioned above, Evolution 3.42.x lags like hell when you type in the HTML email composer, you can type some stuff and wait for a solid 20 seconds for characters to appear for example.

# Conditions

This happens when the laptop is in a dual-screen set up, i.e. where you open the lid from the laptop sitting in the docking station and the built-in screen turns on. As soon as you close the lid, or if you have WebKit2Gtk3 version 2.34 installed instead of 2.36, or if you force WebkitGtk's compositing to be disabled, performance characteristics become normal again.

So, to summarize:

* Intel graphics + Webkit2GTK3 2.36 + dual monitors = problem occurs, making Webkit2Gtk3 unusable
* When running a single monitor, the issue does not occur
* When running Webkit2Gtk3 2.34, the issue does not occur; downgrading webkit2gtk3 from 2.36 to 2.34 and versionlocking it avoids the issue. Upgrading it back to 2.36 causes the issue to immediately reappear
* When running with `WEBKIT_DISABLE_COMPOSITING_MODE=1 evolution`, the issue does not occur even in WebKit2GTK3 2.36.0.

Comment 1 Carlos Garcia Campos 2022-03-31 00:33:18 PDT

Does it happen with 2.34 by using WEBKIT_FORCE_COMPOSITING_MODE=1?

Comment 2 Jeff Fortin 2022-03-31 08:48:25 PDT

Surprisingly indeed, running `WEBKIT_FORCE_COMPOSITING_MODE=1 evolution` while webkit2gtk3 2.34.0 is installed, Evolution's HTML mail composer does not exhibit the performance problems at all, so at first glance it does look like a 2.35/2.36 regression...

Comment 3 Jeff Fortin 2022-03-31 08:58:15 PDT

Actually, ignore my comment #2, it *does* happen with `WEBKIT_FORCE_COMPOSITING_MODE=1 evolution` on webkit2gtk3 2.34.0; I had forgot to turn on my 2nd screen (the laptop lid was closed).