On Fri, 12 Jun 2020, afzal mohammed wrote: > Performance wise, results are not encouraging, 'dd' on tmpfs results, > > ARM Cortex-A8, BeagleBone White (256MiB RAM): > w/o series - ~29.5 MB/s > w/ series - ~20.5 MB/s > w/ series & highmem disabled - ~21.2 MB/s > > On Cortex-A15(2GiB RAM) in QEMU: > w/o series - ~4 MB/s > w/ series - ~2.6 MB/s > > Roughly a one-third drop in performance. Disabling highmem improves > performance only slightly. Could you compare with CONFIG_UACCESS_WITH_MEMCPY as well? Nicolas