[Spice-devel] Should Excel's marching ants animation peg a Radeon Vega 64 to 80-100% GPU usage?

[james harvey]

Is it expected that spice, with host/guest/client on a single pretty
high end system, could play videos decently with little (0-5%)
increase in GPU usage, but that the marching ants animation in Excel
2016 would spike to 80-100% GPU usage and lags the entire system quite
badly?  (Using radeontop to see GPU usage.)  Specifically, it's
"Graphics pipe", "Texture Addresser", "Shader Export", "Shader
Interpolator", "Scan Converter", "Depth Block", and "Color Block".
(I'll note once and a while, for reasons unknown, it gets into a state
where it only spikes to 50-55% usage, but most often it seems to be in
the 80-100% range.)

If I should open a bug for this, please let me know for which package
I should open it on.

Host:
* Arch Linux, near latest releases for everything.  linux 4.19.12,
mesa 18.3.1, qemu 3.1.0, etc.
* Dual 2.9GHz Xeons (32 logical cores)
* 64GB RAM
* Radeon RX Vega 64 (current top of the line Radeon)

Guest:
* QEMU Windows 7
* 8 logical cores (2s/4c/1t)
* 4GB RAM
* QXL 128MB VRAM
* QEMU guest agent
* SPICE Guest Tools

Holding the down key to repeatedly move a cell lower in Excel, even
without causing the screen to scroll, causes a spike to 50-100% GPU
usage as well.  This isn't as horrible, as it only happens when I'm
causing it, unlike the marching ants animation which happens
continually until I press ESC in Excel, or replace the Windows
clipboard with something else.  (So, even if the client is on screen,
but I'm not actively working in it.)

If the marching ants is spiking GPU usage and I minimize the spice
client window, the GPU goes back to normal.

Running Photoshop's marching ants animation causes no significant
increase in GPU usage, granted its animation is different.  Even If I
move part of an image around the screen wildly with my mouse in
Photoshop, the GPU at worst gets to 20%.

If using a remote desktop connection rather than spice, holding the
down key in Excel causes a spike to 50% GPU usage but not up to 100%
like through spice.  Even using best RDP quality to bring back Aero
effects, excel shows a dashed border around a copied cell rather than
an animation, so the marching ants effect isn't comparable.

Am I just seeing how bad not being able to have 2D acceleration in a
Windows guest is?  That it can even peg a Vega 64 at 100% GPU usage?
Maybe for some reason Excel is more 2D intensive than wildly moving
part of an image in Photoshop?  (Like maybe Excel is doing as many
"frames" per second as it can, but Photoshop is limiting?)

Tagged Victor Toso, in case this has any relationship to the clipboard
bug at https://gitlab.freedesktop.org/spice/win32/vd_agent/issues/6

I only started noticing it once the clipboard bug was fixed for me, as
before then the marching ants animation would go away pretty quickly
due to that bug.

I am running spice/spice-gtk/spice-protocol git versions with the
patch for that bug, however I downgraded to released versions spice
0.14.0, spice-gtk 0.35, and spice-protocol 0.12.14, to make sure this
GPU usage isn't related to unreleased commits.

I might see if I can just get the marching ants animation disabled,
but wanted to start here first in case it's a bug that could help
performance elsewhere as well.