[Spice-devel] Testing playback of flash videos at 1920x1080

[Hans de Goede]

Hi all,

As we've had some reports that flash videos (from for example youtube) do not work
well when full-screened with a monitor running at 1920x1080, I've been running some
tests.

Here are the results:

-server: F-14 + spice + qemu 0.4, from:
  git clone git://git.engineering.redhat.com/users/ehabkost/qemu-kvm-rhel6.git --branch rhel6/master
  git clone git://git.engineering.redhat.com/users/ulublin/spice.git
  AMD Phenom(tm) II X4 945 Processor
  4G RAM
  Guest: 1 "core" cpu, 2G RAM, windows XP + ie8 + flash 10.1 with spice display driver
         and agent.

  -client: on same machine, Radeon X1950 Pro, fullscreen to 1920x1080
   a 480 p youtube video
   qemu cpu load: 150%
   xorg cpu load:  70%
   spicec cpu ld:  20%

  -Same as above with compositing desktop:
   qemu cpu load: 140%
   xorg cpu load:  30%
   spicec cpu ld:  30%

  -client: Athlon 64 X2 5000+, 2 GB RAM, Radeon 9250 (agp), 100mbit connection
   to server. RHEL-6 + RHEL-6 spice-client
   Fullscreen to 1920x1080 a 480 p youtube video
   qemu cpu load: 150%
   xorg cpu load:  60%
   spicec cpu ld:  30%

  -Same as above with compositing desktop:
   qemu cpu load: 140%
   xorg cpu load:  65%
   spicec cpu ld:  25%

  -client: Intel Q8200, 1 GB RAM, integrated Intel graphics, 100mbit
   connection to server. RHEL-6 + RHEL-6 spice-client
   spice-client running windowed at a size of 1920x1080, only 1280x1024
   shown (small monitor). Fullscreen to 1920x1080 a 480 p youtube video
   qemu cpu load: 150%
   xorg cpu load:   7%
   spicec cpu ld:  20%

  -client: AMD Athlon X4 630, 4GB RAM, Radeon HD 5450, 100mbit
   connection to server. RHEL-6 + RHEL-6 spice-client
   Fullscreen to 1920x1080 a 480 p youtube video
   qemu cpu load: 150%
   xorg cpu load:  20%
   spicec cpu ld:  30%

-server: F-14 + spice-master + spice/qemu master
  AMD Phenom(tm) II X4 945 Processor
  4G RAM
  Guest: 1 "core" cpu, 2G RAM, windows XP + ie8 + flash 10.1 with spice display driver
         and agent.

  -client: on same machine, Radeon X1950 Pro, fullscreen to 1920x1080
   a 480 p youtube video
   qemu cpu load: 125%
   xorg cpu load:  70%
   spicec cpu ld:  15%


###

Running taskmanager in windows reveals flash (ie) using 100% cpu, which
matches the 100% + qemu process load. I believe the problem is that when
running with the qxl display driver flash cannot use any gpu acceleration
so it needs to do everything in software and simply cannot handle this at
1920x1080p. Short of gpu accel the only other possible fix would be
a more powerful cpu.

This also matches my experience with fullscreen flash video under Linux,
which also becomes cpu and leads to 100% cpu load. The problem is that
without gpu accel flash does all rendering itself and renders (including
decoding, scaling, etc.) the movie at 1920x1080 fully in software, it does
this as the ui elements are a transparent overlay and it wants to render
these at the native screen resolution rather then scaling and ends up
rendering everything in software which takes ages. This is a well
known flash problem, just google for "flash slow".

Regards,

Hans