netdev - Re: [PATCH/RFC net-next] rocker: remove rocker parameter from functions that have rocker

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Date:	Mon, 1 Jun 2015 13:25:25 +0900
From:	Simon Horman <simon.horman@...ronome.com>
To:	Scott Feldman <sfeldma@...il.com>
Cc:	David Laight <David.Laight@...lab.com>,
	Jiri Pirko <jiri@...nulli.us>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH/RFC net-next] rocker: remove rocker parameter from
 functions that have rocker_port parameter

On Thu, May 28, 2015 at 08:53:20AM -0700, Scott Feldman wrote:
> On Thu, May 28, 2015 at 2:18 AM, David Laight <David.Laight@...lab.com> wrote:
> > From: Simon Horman
> >> Sent: 28 May 2015 04:23
> >> The rocker (switch) of a rocker_port may be trivially obtained from
> >> the latter it seems cleaner not to pass the former to a function when
> >> the latter is being passed anyway.
> >
> > If the arguments are passed in registers (they almost certainly are)
> > or the function is inlined (possible since they are static) and
> > the calling code already has both values in registers then
> > passing both values saves a memory read inside the called code.
> >
> > So on 'hot paths' it probably makes sense to pass both values.
> 
> Agreed, and Simon's patch is 99% cold path, so I'd rather trade
> clarity in the code than saving a nanosec in a driver cold path.
> 
> Simon, would you respin, remove rocker_port_rx_proc() changes, remove
> RFC, and add my ack?  rocker_port_rx_proc() was the only hot path case
> I found.

Sure, that seems reasonable to me. I have done so.
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