Created attachment 150562 [details] KWin - start dragging SUMMARY When I start moving windows by dragging, I experience a slight but disrupting delay between the time I pressed/started dragging, and the time a window actually starts changing its position in response. All frames in between are skipped, so it feels like a "jump". STEPS TO REPRODUCE 1. Start dragging a window. OBSERVED RESULT A disrupting delay. EXPECTED RESULT No delay. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE: git master Qt Version: 5.15.5 Kernel Version: 5.18.10-arch1-1 (64-bit) Graphics Platform: X11 Processors: 8 × Intel® Core™ i7-6700HQ CPU @ 2.60GHz Memory: 15.6 GiB of RAM Graphics Processor: NVIDIA GeForce GTX 970M/PCIe/SSE2 Manufacturer: ASUSTeK COMPUTER INC. Product Name: G752VT System Version: 1.0 ADDITIONAL INFORMATION It happens consistently every time. Workaround: press and hold for a split of a second before start dragging, kinda like give it some time to warm up. It happens both with Wobbly Windows effect and without it. It happens regardless of which part of the window you start dragging from (decorations or empty part of a body), or even a Meta+drag.
New discovery: This problem is gone when plasmashell is dead. KWin becomes fully responsive again. Pre-history: I updraged my Arch today, restarted plasma — and it crashed on start. *Sigh* I should've known to rebuild kde from git master first. Three hours in, it's still rebuilding (basically from scratch, nuking old build directory, because the very gcc was upgraded too), plasma is still dead — no desktop or panels, but most importantly: windows start moving and resizing immediately upon press & drag. KWin is as responsive as is could get.