Re: [PATCH v3 0/3] riscv: optimized mem* functions

From: Guo Ren
Date: Mon Jun 21 2021 - 22:40:05 EST


On Tue, Jun 22, 2021 at 9:09 AM Nick Kossifidis <mick@xxxxxxxxxxxx> wrote:
>
> Hello Matteo,
>
> Στις 2021-06-17 18:27, Matteo Croce έγραψε:
> > From: Matteo Croce <mcroce@xxxxxxxxxxxxx>
> >
> > Replace the assembly mem{cpy,move,set} with C equivalent.
> >
> > Try to access RAM with the largest bit width possible, but without
> > doing unaligned accesses.
> >
> > Tested on a BeagleV Starlight with a SiFive U74 core, where the
> > improvement is noticeable.
> >
>
> There are already generic C implementations for memcpy/memmove/memset at
> https://elixir.bootlin.com/linux/v5.13-rc7/source/lib/string.c#L871 but
> are doing one byte at a time, I suggest you update them to do
> word-by-word copy instead of introducing yet another memcpy/memmove C
> implementation on arch/riscv/.
Yes, I've tried to copy the Glibc version into arch/csky/abiv1, and
Arnd suggested putting them into generic.
ref: https://lore.kernel.org/linux-arch/20190629053641.3iBfk9-I_D29cDp9yJnIdIg7oMtHNZlDmhLQPTumhEc@z/#t

>
>
>



--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/