keyboard input is not processed in the right order during high CPU load times

[Stephane Lapie]

I have noticed several issues with keyboard input processing, that can all seemingly be tied to high CPU usage.

For context, I am using a french keyboard, and also need to type Japanese, which has me using IBus and Anthy.

I think at some point in Ubuntu, the way input was handled changed drastically, and ever since I have been dealing with the following issues :
- Composite keys such as ^ (^ + e => ê) used in French for accents are processed in a weird way :
Suppose I type "Le verbe être est",
I sometimes end up with "Le verbe treê est" actually appearing when typing under high CPU load. (Hinting at the fact that the ^ key stroke processing happens asynchronously, and without accounting for the proper and expected order of strokes, which is extremely annoying)

(I mainly see this specific problem in applications such as Chrome, Skype for Linux Alpha, Discord, Slack.)

Before I found a suggestion to set IBUS_ENABLE_SYNC_MODE=1 in my session environment, keyboard input order would end up completely shuffled. Enforcing sync mode nearly fixed everything except for composite keys.

- When switching between French and Japanese, I have defined a specific shortcut to do the switching for me, and I am used to the switching taking time. The problem is that switching does not lock any input after that, so that it would be processed AFTER the switch was complete.
When typing "<switch>tesuto" I expect the following to be input : てすと
But I get the following : teすと

This one, I am thinking is caused by asynchronous input processing for the shortcut keys, and the Anthy process taking time to get called back from swap memory. I would be perfectly fine with the previous behavior, and waiting three seconds, as long as input would be processed all at once, in the order I typed it.

The above two problems mean I have to actually watch at what times I am going to need to use accented characters, or to type Japanese, and WAIT for the computer to finish switching before resuming typing.

These literally halve my typing speed because I can't rely on muscle memory anymore when typing any language other than English.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: ibus 1.5.10-1ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-35.40-generic 4.2.8-ckt5
Uname: Linux 4.2.0-35-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
CurrentDesktop: GNOME-Flashback:Unity
Date: Sun Oct 30 20:45:04 2016
InstallationDate: Installed on 2010-01-30 (2464 days ago)
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027.1)
SourcePackage: ibus
UpgradeStatus: Upgraded to wily on 2016-04-16 (196 days ago)

[Adolfo Jayme Barrientos (fitojb)]

I’ve been bit too many times by this :-)