Re: [PATCH 1/3] riscv: optimized memcpy

From: Emil Renner Berthing
Date: Tue Jun 15 2021 - 12:12:46 EST


On Tue, 15 Jun 2021 at 15:29, Bin Meng <bmeng.cn@xxxxxxxxx> wrote:
> ...
> Yes, Gary Guo sent one patch long time ago against the broken assembly
> version, but that patch was still not applied as of today.
> https://patchwork.kernel.org/project/linux-riscv/patch/20210216225555.4976-1-gary@xxxxxxxxxxx/
>
> I suggest Matteo re-test using Gary's version.

That's a good idea, but if you read the replies to Gary's original patch
https://lore.kernel.org/linux-riscv/20210216225555.4976-1-gary@xxxxxxxxxxx/
.. both Gary, Palmer and David would rather like a C-based version.
This is one attempt at providing that.

> > I'm surprised IP_NET_ALIGN isn't set to 2 to try to
> > avoid all these misaligned copies in the network stack.
> > Although avoiding 8n+4 aligned data is rather harder.
> >
> > Misaligned copies are just best avoided - really even on x86.
> > The 'real fun' is when the access crosses TLB boundaries.
>
> Regards,
> Bin