http://bugzilla.opensuse.org/show_bug.cgi?id=1112824 http://bugzilla.opensuse.org/show_bug.cgi?id=1112824#c36 --- Comment #36 from Robert Munteanu <rombert@apache.org> --- (In reply to Michiel Janssens from comment #33)
There is a possibility that the spectre mitigations have something to do with all this, and or hyperthreading/smt. I tested my system on the impact of those mitigations. As a reference I used a mouse click on "Show applications" item on the gnome-shell menu, running wayland. Watching if the application icons transition smoothly from the corner into the main desktop area. Hardware: Dell XPS 13 9360 Snapshot 20181118 Kernel 4.19.2-1
My subjective results 1. boot with default kernel parameters Transition is barely noticeable, not smooth for sure
2. boot with kernel parameters: pti=off spectre_v2=off l1tf=off nospec_store_bypass_disable no_stf_barrier Transition is very smooth
3. boot with kernel parameters: spectre_v2=off Transition is smooth This parameter seems to have the biggest impact of all the tested parameters.
Now I read about the new recently disclosed spectre v2 vulnerabilities and the STIBP mitigation. Some voices say that we might as well disable hyperthreading/smt instead of these new mitigations.
4. boot with default kernel parameters, and hyperthreading disabled in BIOS Transitions are smooth.
For the moment I will leave all mitigations enabled and hyperthreading disabled. For the record, this is an Intel Kabylake cpu
Some more data points: - for my Lenovo W541 laptop - i7-4810MQ with iGPU, none of these helped. The animations are maybe slightly faster, but still laggy - after updating my desktop ( Ryzen 5 2600X, Nvidia 1070, Samsung EVO 970 NVME SSD ) from Gnome 3.28, the animations are smooth, but I feel I slight stutter when pressing buttons for the first time, e.g. the applications button. Maybe I'm imagining, I don't now. What I think would be useful is for those affected and for which the various boot options worked to clarify whether they were using a discrete GPU or the integrated GPU. -- You are receiving this mail because: You are on the CC list for the bug.