Re: [External] Re: [PATCH] riscv: Improve sbi_ecall() code generation by reordering arguments

From: yunhui cui
Date: Mon Mar 25 2024 - 08:44:57 EST


Hi Alex,

On Mon, Mar 25, 2024 at 2:20 AM Alexandre Ghiti <alexghiti@rivosinccom> wrote:
>
> Hi Qingfang,
>
> On Sat, Mar 23, 2024 at 7:26 AM Qingfang Deng <dqfext@xxxxxxxxx> wrote:
> >
> > Hi Alexandre,
> >
> > You can simply make sbi_ecall `__always_inline`, so the C function call
> > overhead can be fully avoided.
>
> I understand your point, though I don't think we need to mark
> sbi_ecall() as inline, it's not in any hot path so it's not worth it.
> This patch simply gets rid of a really useless overhead, but it does
> not visibly accelerate anything.
>
> I hope it makes sense,
>
> Thanks,
>
> Alex
>

The compiler will have inline size restrictions, so I agree with the
modification of this patch instead of inline.
Please refer to:
https://github.com/gcc-mirror/gcc/blob/master/gcc/common.opt,
"finline-limit-"

So:
Reviewed-by: Yunhui Cui <cuiyunhui@xxxxxxxxxxxxx>

Thanks,
Yunhui