On Sat, Jul 26, 2014 at 02:44:13AM +0000, Caoqiuhong wrote: > The CPU model we use is big.LITTLE(4@A7, 4@A15), yes, it support using all 8 > cores at once, and application could switch between A15 and A7 cluster. > Now three SOC support 8 cores run at once, Exynos 5422, Kirin920 (these two > are big.LITTLE cpu), MT6592 (8 cores A7). > > >>If it uses all 8 cores at once, is the cache coherency correctly enabled > >>(The CCI)? > Yes, CCI enabled, in order to ensure the cache coherency between each core in > different clusters, only enable CCI could make 8 core run at once. > I don't think the CCI cause the this issue. because MT6592 device is 8 core > A7, no CCI feature, also have the same problem.
Yeah that does sound like it rules out caching issues. > >>I have a system on my desk with 8 cores but the kernel doesn't support > >>using the A7 cores yet (I should check if that has been fixed yet or not). > You said BSP in you device doesn't support A7. Is that mean only run 4@A15 > core at once? > Could you tell me what 8 cores device you use? As I know, only few devices > support 8 cores now. > Such as Galaxy S5(Exynos 5422), Honor 6(Kirin 920), and some MT6592 devices. I have an exynos5420 board (arndale-octa). I know it is being worked on, but last I checked it wasn't working yet for the A7 cores (trying to boot the A7 cores caused an exception from the secure firmware). I am building a new kernel to see if it has gotten better now. I think the android builds for the board do support running in cluster mode (so all A15 or all A7) but I couldn't care less about running android. -- Len Sorensen _______________________________________________ Pixman mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/pixman
