From: Simon Horman <simon.horman@netronome•com>
To: Scott Feldman <sfeldma@gmail•com>
Cc: David Laight <David.Laight@aculab•com>,
Jiri Pirko <jiri@resnulli•us>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>
Subject: Re: [PATCH/RFC net-next] rocker: remove rocker parameter from functions that have rocker_port parameter
Date: Mon, 1 Jun 2015 13:25:25 +0900 [thread overview]
Message-ID: <20150601042522.GA6026@vergenet.net> (raw)
In-Reply-To: <CAE4R7bC7qt9LhDqvpb-ZvWB6te=nf4DgXrC0T4NT7DX2yrCgrw@mail.gmail.com>
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@aculab•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.
prev parent reply other threads:[~2015-06-01 4:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-28 3:23 [PATCH/RFC net-next] rocker: remove rocker parameter from functions that have rocker_port parameter Simon Horman
2015-05-28 5:11 ` Scott Feldman
2015-05-28 6:15 ` Jiri Pirko
2015-05-28 8:30 ` Simon Horman
2015-05-28 9:18 ` David Laight
2015-05-28 15:53 ` Scott Feldman
2015-06-01 4:25 ` Simon Horman [this message]
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