Official sunxi OpenEmbedded layer for Allwinner-based boards.
This layer depends on the additional layer:
Tested with core-image-base.
- Nicolas Aguirre firstname.lastname@example.org
- Enrico Butera email@example.com
- Sergey Lapin firstname.lastname@example.org
The default machine settings are meant to be the lowest common denominator, maximizing generality. Significantly better performance (2x-3x) can be achieved with the following settings:
For Allwinner A20 (Cubieboard2/CubieTruck), the following tuning options are recommended:
Enable hardfloat, thumb2 and neon capabilities
DEFAULTTUNE = "cortexa7hf-neon-vfpv4"
This tuning profile takes advantage of the Allwinner A20 hardfloat, neon and vfpv4 capabilities.
Change CPU governor to ondemand, and tune settings
echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor echo 336000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq echo 912000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq #More aggressive #echo 1008000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq echo 40 > /sys/devices/system/cpu/cpufreq/ondemand/up_threshold echo 200000 > /sys/devices/system/cpu/cpufreq/ondemand/sampling_rate
This code changes the default CPU governor from fantasy to ondemand, and tunes its settings, as recommended at http://linux-sunxi.org/Cpufreq
For additional discussion, see https://github.com/linux-sunxi/meta-sunxi/issues/25