ARM big.LITTLE Processing Demo (HMP) on ARM TC2 Test Chip
Samsung launched Exynos 5 Octa at CES 2013. This processor comes with 8 cores: 4 Cortex A15 cores and 4 Cortex A7 cores, and it’s the first processor that’s been announced to work in big.LITTLE configuration, where the big cores (A15) handle demanding tasks, and the LITTLE cores (A7) handle simpler tasks such as audio playback or background tasks. This is all done to optimize power consumption. There are 2 big.LITTLE software implementations: In-kernel switcher (IKS) and heterogeneous multi-processing (HMP). The first one is easier to implements but can only use 4 cores (in Exynos 5 Octa) at a time, and the second is more complex, but can handle all 8 cores, and assign individual tasks to a particular core. For more technical details about big.LITTLE implementations, you can read my previous post.
ARM and Samsung recently uploaded a video providing an overview of big.LITTLE (but instead of IKS and HMP, it’s called “Cluster Migration Mode” and “Full MP”), and showing an interesting demo (2:44) running on TC2 development platform (2x A15, 3x A7, no GPU) that shows the load all five cores, power consumption on the big cluster and LITTLE cluster, which all vary depending on the tasks. This demo runs in Linaro Android with HMP/Full MP implementation, and the software showing the load and power consumption must be ARM Development Studio 5 (DS5).