Comment 14 for bug 880707

Revision history for this message
Daniel van Vugt (vanvugt) wrote : Re: [regression] Visible tearing is worse in 11.10 than 11.04, even when "Sync To VBlank" is enabled, but only when Unity is active.

Experimental fixes for this and related performance bugs are now available
for testing in ppa:vanvugt/compiz and ppa:vanvugt/unity. For the best
results I recommend trying both together. But testing them individually is
useful too.

IMPORTANT NOTES:

  * The fixes in ppa:vanvugt/compiz REQUIRE that "Sync To VBlank" is ENABLED
    in CompizConfig Settings Manager (OpenGL section).
    This is the default setting when Ubuntu 11.10 is installed.

  * When using ppa:vanvugt/compiz you should DISABLE the workaround
    "Force full screen redraws (buffer swap) on repaint" in
    CompizConfig Settings Manager (Workarounds section).
    This is the default setting when Ubuntu 11.10 is installed.

  * I don't claim to have fixed all tearing. I only claim that the amount of
    tearing in oneiric with the fix is no longer worse than in natty.

  * nouveau: If you are using the "nouveau" driver for NVIDIA chips you will
    need to enable sync-to-vblank support in the driver options because
    nouveau has it disabled by default. You can do this by editing
    /etc/X11/xorg.conf and adding:
       Section "Device"
           Identifier "My Graphics"
           Option "GLXVBlank" "on"
       EndSection
    Then log out and in again for it to take effect.

  * fglrx (Catalyst): The fglrx driver also disables sync-to-vBlank support
    by default. To fix this:
      1. Open Catalyst Control Center.
      2. Go to 3D > More Settings.
      3. Set "Wait for vertical refresh" to
         "On, unless application specifies".

  * Please don't try using the Benchmark plugin in compiz-plugins-extra
    because it is broken and misleading (bug 898548).

Please leave feedback in the relevant bug reports.

- Daniel

---

ppa:vanvugt/compiz | https://launchpad.net/~vanvugt/+archive/compiz
compiz (1:0.9.6+bzr20110929-0ubuntu6vv2) oneiric

  * Added proposed fix for inaccurate frame timing causing tearing and
    stuttering.
    (LP: #880707) (LP: #888039) (LP: #92599) (LP: #798868) (LP: #876575)

ppa:vanvugt/unity | https://launchpad.net/~vanvugt/+archive/unity
unity (4.24.0-0ubuntu2b1vv4) oneiric; urgency=low

  * Fix major performance regressions due to unnecessary UnityFBO binding
    (LP: #861061) (LP: #880707)
    UnityFBO was being bound even when not required. This caused major lag in
    glPaintOutput, which slowed down all rendering. This was seen in reduced
    framerates in apps (LP: #861061) and significantly worse screen tearing
    with Unity 4.x compared to 3.x (LP: #880707).