[PATCH 0/1] __asm_copy_to-from_user: Reduce more byte_copy
Akira Tsukamoto
akira.tsukamoto at gmail.com
Fri Jul 30 06:50:52 PDT 2021
Adding none unrolling word_copy, which is used if the size is smaller
than 9*SZREG.
This patch is based on Palmer's past comment.
> My guess is that some workloads will want some smaller unrolling factors,
It will reduce the number of slow byte_copy being used when the
size is small.
Have tested on qemu rv32, qemu rv64 and beaglev beta board.
In the future, I am planning to convert uaccess.S to inline assembly
in .c file. Then it will be easier to optimize on both in-order core and
out-of-order core with #ifdef macro in c.
Akira Tsukamoto (1):
riscv: __asm_copy_to-from_user: Improve using word copy if size <
9*SZREG
arch/riscv/lib/uaccess.S | 46 ++++++++++++++++++++++++++++++++++++----
1 file changed, 42 insertions(+), 4 deletions(-)
--
2.17.1
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