Re: [PATCH net-next 05/10] net: hns3: using modulo for cyclic counters in hclge_cmd_send

[lipeng (Y)]

On 2018/6/30 20:03, David Miller wrote:
> From: Peng Li <lipeng321@xxxxxxxxxx>
> Date: Fri, 29 Jun 2018 19:23:00 +0800
>
> > @@ -228,8 +228,7 @@ int hclge_cmd_send(struct hclge_hw *hw, struct hclge_desc *desc, int num)
> >   		desc_to_use = &hw->cmq.csq.desc[hw->cmq.csq.next_to_use];
> >   		*desc_to_use = desc[handle];
> >   		(hw->cmq.csq.next_to_use)++;
> > -		if (hw->cmq.csq.next_to_use == hw->cmq.csq.desc_num)
> > -			hw->cmq.csq.next_to_use = 0;
> > +		hw->cmq.csq.next_to_use %= hw->cmq.csq.desc_num;
> >   		handle++;
> I would advise against this.
>
> The "%" modulus operation takes many cpu cycles, and the current code
> is thus much faster.
>
> .
Agree with you.

Thanks for your review, we concentrate on the code style and ignore the
performance in this patch, It is not good.

I will remove this patch from the patchset.

>