I am interested in buying a Juno development board, but have a set of technical questions related to the platform, namely:
(1) What are the migration modes that are available on the ARMv8 big.LITTLE? In particular, can I use both Cluster and Global Task Migration modes and can we apply DVFS?
(2) Can I have access to the performance counters (I have bought an Odroid XU E board, but am unable to read from the performance counters)?
(3) Does the board provide OpenCL support for either the CPU or the GPU?
Hi,
1)
Juno is supported by a couple of software stacks, which are available via Linaro:
http://releases.linaro.org/latest/members/arm/openembedded/juno-lsk
http://releases.linaro.org/latest/members/arm/android/images/armv8-android-juno-lsk
These include big.LITTLE MP support - so (in brief) that's heterogeneous scheduling amongst both the A57 & A53 CPUs. There's no direct support for the older cluster switching model.
A DVFS framework is supported
2)
Yes the Linaro kernel supports perf and you should be able to access PMU counts on Juno
3)
There are plans to provide OpenCL support fro the GPU as part of the Android software stack - but quoting from the ASOP filesytem comments in the link above: "OpenCL support is not present at this time and will be enabled in a future release"
Hope that helps with some of your questions.
MarkN.