Hi all I'm trying to figure out how to increase performance on audio reading using the mmap interface. Right now what I understand it's that allocation comes from core/memalloc.c ops that allocate the memory for dma under driver/dma. The reference platform I have is an imx8mm and the allocation in arm64 is: 0xffff800011ff5000-0xffff800012005000 64K PTE RW NX SHD AF UXN MEM/NORMAL-NC This is the reason that is allocated for dma interface. Now access linear on the multichannel interface the performance is bad but worse if I try to access a channel a time on read. So it looks like it is better to copy the block using memcpy on a cached area and then operate on a single channel sample. If it's correct what I'm saying the mmap_begin and mmap_commit basically they don't do anything on cache level so the page mapping and way is used is always the same. Can the interface be modified to allow cache the area during read and restore in the commit phase? Michael
