Very slow rendering on ASUS Nexus 7, ARM, Tegra 3
Submitted by marmuta
Assigned to Chris Wilson
Created attachment 69773 cairo-perf results for Onboard starting up with Ambiance theme
I'm investigating why Onboard with the default theme takes upwards of 30s to start up on a Nexus 7 with Ubuntu 12.10. It's barely usable even with the simplest themes, where just a plain filled and stroked rectangle is drawn per key.
A cairo-perf-trace of Onboard starting up shows the Nexus 7 to be ~200x slower than a Sandy Bridge i3 laptop, but single-threaded CPU performance differs just by a factor of roughly 4.5 (see Attachment). Also the cairo image backends are vastly faster than the xcb/xlib one's, which is the reverse of the i3's results.
The Nexus 7 has a quad-core Tegra 3, me thinks the hardware isn't necessarily the limiting factor. Is this a driver issue? Xorg takes close to 100% CPU during heavy cairo rendering with (python-based) Onboard.
Here's the original bug report: https://bugs.launchpad.net/ubuntu-nexus7/+bug/1070760
gtkperf on the Nexus 7: GtkPerf 0.40 - Starting testing: Thu Nov 8 18:58:56 2012
GtkEntry - time: 0.77 GtkComboBox - time: 17.09 GtkComboBoxEntry - time: 6.95 GtkSpinButton - time: 2.42 GtkProgressBar - time: 2.91 GtkToggleButton - time: 7.59 GtkCheckButton - time: 2.12 GtkRadioButton - time: 3.66 GtkTextView - Add text - time: 6.94 GtkTextView - Scroll - time: 1.13 GtkDrawingArea - Lines - time: 12.66 GtkDrawingArea - Circles - time: 27.67 GtkDrawingArea - Text - time: 19.19 GtkDrawingArea - Pixbufs - time: 2.31
Total time: 113.47
libcairo2 1.12.2-1ubuntu2 nvidia-tegra3 binary Xorg driver 16.0-0ubuntu3
Attachment 69773, "cairo-perf results for Onboard starting up with Ambiance theme":