Closed Bug 846100 Opened 7 years ago Closed 4 years ago
Fix bad performance of b2g on pandaboards
We can get pandaboards in quantity and they can be shared across android and b2g testing, so they're perfect for larger-scale automation. The problem is, jgriffin tells me they're basically unusable for b2g perf testing because the UI runs at something like 2fps. We want to investigate and fix that problem. Is it a problem with running at high resolution? What do quick gecko profiler or |perf| runs say is slow? Are we lacking some system "perf sauce", for example a missing vendor gralloc driver?
jgriffin tells me that fennec-on-android runs fine on these devices, so hopefully there's a small configuration issue.
android on panda runs at 720p, we have 1280x672 available to work with. Maybe it is a special video/graphics driver rolled into linaro which isn't included in the b2g builds that we run on the panda boards.
The Pandaboards are supported by AOSP, right? So we should have all the right driver blobs etc? Logcat output from a pandaboard boot would be interesting to look at.
When I once profiled b2g on the pandas, a lot of time was spend in some of pixman's functions, which sounds a lot like software rendering to me. Maybe we need to change some of the rendering code or setup to use hardware acceleration. We use the 'official' graphics driver that comes from Imgtec. The driver consists of a kernel and a (closed-source) user-space component. A problem here is that kernel and user-space graphics drivers cannot be replaced easily. There is afaik only one user-space driver and it only works with certain kernel drivers.
Cool, thanks. We should see how perf changes if we downgrade the resolution to HVGA or WVGA.
Today I learned about a newer user-space driver for the graphics than the one we currently use. Maybe it fixes some of the problems. But this will need a new kernel, I guess. The user-space binary is available from https://dl.google.com/dl/android/aosp/imgtec-panda-20120807-c4e99e89.tgz
Pandas were abandoned for b2g and are also no longer used at all at mozilla.
Status: NEW → RESOLVED
Closed: 4 years ago
Resolution: --- → WONTFIX
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