Dash menu and task switcher appear and disappear at < 1 FPS

[Alan Hoyle]

1. Description: Ubuntu 16.04.1 LTS
Release: 16.04

2. Compiz, Unity, nvidia driver,card versions:
[alanh:~] $ apt-cache policy compiz
compiz:
  Installed: 1:0.9.12.2+16.04.20160823-0ubuntu1
  Candidate: 1:0.9.12.2+16.04.20160823-0ubuntu1
  Version table:
 *** 1:0.9.12.2+16.04.20160823-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages
        100 /var/lib/dpkg/status
     1:0.9.12.2+16.04.20160415-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu xenial/main i386 Packages
[alanh:~] $ apt-cache policy unity
unity:
  Installed: 7.4.0+16.04.20160906-0ubuntu1
  Candidate: 7.4.0+16.04.20160906-0ubuntu1
  Version table:
 *** 7.4.0+16.04.20160906-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     7.4.0+16.04.20160415-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
[alanh:~] $ sudo lshw -C display ; dpkg -l | grep nvidia
  *-display
       description: VGA compatible controller
       product: G98 [Quadro NVS 295]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:29 memory:de000000-deffffff memory:c0000000-cfffffff memory:dc000000-ddffffff ioport:dc80(size=128) memory:dfd00000-dfd1ffff
ii nvidia-340 340.96-0ubuntu3+gpu16.04.1 amd64 NVIDIA binary driver - version 340.96

3. The unity menu or task switcher pop up or leave quickly
4. The menu or task switcher slowly fade in (or out) over the course of 5-7 seconds.

I'm running Ubuntu 16.04 with the latest updates on a 2009 Dell T5500 workstation with an nvidia Quadro NVS card. When I run the noveau drivers, I get errors and lockups, so I run the nvidia 340 drivers (which are the recommended ones). I've tried a few other versions of the drivers, and still get the same issues.

The problem that I have is that on initial login, the Unity menu and alt-tab switchers work quickly, but after I've left the X session up for a while, they start popping up at about 1 FPS over the the course of 5-10 seconds. Switching to a different desktop (e.g. MATE) "fixes" the issue, but I like the easy "search for applications" launcher that Unity provides.

The dash "include online search results" is off, but I think that was a red herring, given that the alt-tab switcher exhibits the same behavior. I've tried toying with CompizConfig settings (e.g. Dash Blur, disabling animations, etc), to no avail.

I just did a fresh install of 16.04 yesterday on a brand new, recent SSD, and I'm getting the same issues, and I'd seen the same issue going back at least to 14.04.
Note that running $ unity --replace or compiz --replace does not alleviate the problem for more than a couple of minutes.

I've installed the CompizConfig Settings Manager and tried disabling anything that seemed relevant: Animations, Fading Windows, Window Decoration, Dash Blur, etc. Even if I choose Enable Low Graphics Mode, the affected windows don't pop up instantly. I've even gone into the Ubuntu Unity Plugin and set all of the Menus durations to 0, to no avail.

When running htop -d 1 (i.e. to get quick updates on the CPU usage in tenths of a second), I see a brief spike in CPU utilization from compiz and /usr/lib/xorg/Xorg during the issue, and compiz stays pegged using a full CPU until the problematic window goes away. (CPU is 4 core hyperthreaded Xeon)

If there exists a work-around, I've also asked a question on askubuntu.com

http://askubuntu.com/questions/827468/unity-menu-fast-when-first-logged-in-then-gets-progressively-slower

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: unity 7.4.0+16.04.20160906-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-38.57-generic 4.4.19
Uname: Linux 4.4.0-38-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
.proc.driver.nvidia.gpus.0000.03.00.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0000:03:00.0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 340.96 Sun Nov 8 22:33:28 PST 2015
 GCC version: gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.2)
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Fri Sep 23 13:21:14 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
DkmsStatus: nvidia-340, 340.96, 4.4.0-38-generic, x86_64: installed
GraphicsCard:
 NVIDIA Corporation G98 [Quadro NVS 295] [10de:06fd] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: NVIDIA Corporation G98 [Quadro NVS 295] [10de:062e]
GsettingsChanges:
 b'org.compiz.core' b'hsize' b'2'
 b'org.compiz.core' b'active-plugins' b"['core', 'composite', 'opengl', 'wall', 'imgpng', 'compiztoolbox', 'vpswitch', 'resize', 'commands', 'regex', 'unitymtgrabhandles', 'grid', 'place', 'copytex', 'move', 'snap', 'mousepoll', 'animation', 'expo', 'session', 'ezoom', 'workarounds', 'fade', 'scale', 'unityshell']"
 b'org.compiz.core' b'vsize' b'2'
 b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'"
 b'org.gnome.desktop.interface' b'scaling-factor' b'uint32 1'
InstallationDate: Installed on 2016-09-19 (3 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
MachineType: Dell Inc. Precision WorkStation T5500
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-38-generic root=UUID=35e12aca-d597-49fb-9595-58c9990201fa ro quiet splash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/09/2009
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A01
dmi.board.name: 0D883F
dmi.board.vendor: Dell Inc.
dmi.board.version: A04
dmi.chassis.type: 7
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA01:bd03/09/2009:svnDellInc.:pnPrecisionWorkStationT5500:pvr:rvnDellInc.:rn0D883F:rvrA04:cvnDellInc.:ct7:cvr:
dmi.product.name: Precision WorkStation T5500
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.12.2+16.04.20160823-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.2
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2.2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2.2
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Thu Sep 22 11:33:43 2016
xserver.configfile: default
xserver.errors: open /dev/fb0: No such file or directory
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.18.3-1ubuntu2.3