From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lars Melin Subject: Re: [PATCH net-next v2 00/12] cdc_ncm: add buffer tuning and stats using ethtool Date: Mon, 19 May 2014 00:10:29 +0700 Message-ID: <5378E985.1040206@gmail.com> References: <1400269709-18854-1-git-send-email-bjorn@mork.no> <20140516.224032.2301577488192248796.davem@davemloft.net> <87d2fcoqay.fsf@nemi.mork.no> <20140518011917.11270.qmail@stuge.se> <87vbt3m98p.fsf@nemi.mork.no> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , netdev@vger.kernel.org, linux-usb@vger.kernel.org, alexey.orishko@gmail.com, oliver@neukum.org, David.Laight@aculab.com To: =?UTF-8?B?QmrDuHJuIE1vcms=?= , Peter Stuge , Enrico Mioso Return-path: Received: from mail-pb0-f54.google.com ([209.85.160.54]:44374 "EHLO mail-pb0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752121AbaERRKn (ORCPT ); Sun, 18 May 2014 13:10:43 -0400 In-Reply-To: <87vbt3m98p.fsf@nemi.mork.no> Sender: netdev-owner@vger.kernel.org List-ID: On 2014-05-18 21:50, Bj=C3=B8rn Mork wrote: > I could be wrong, but my impression is that the userspace API > preferences for network devices are > > 1. ethtool > 2. sysfs > 3. module param > .. > 99. ioctl > > This is the primary reason why I was looking for someplace to put thi= s > within the existing ethtool API. Using sysfs would have worked fine > too, I guess. But is there any real advantage, making it worth a > switch? I am all open to change to sysfs instead before v3.16 is > released, *if* there are good reasons to do it. And no objections. B= ut > I do want more of a reason than the fact that it can be done. Maybe = I > got the preferred order wrong? > > I ruled out module parameters early because I believe there are real = use > cases requiring different settings per device. The limited host syst= em > resources will of course affect all devices on a single host the same > way. But not all devices can cope with the reduced buffers. So there > should be some way to tune two devices connected to the same host > differently. > > I am not going to say anything about ioctls :-) > > > Bj=C3=B8rn > -- Your target audience is embedded systems with limited cpu power and=20 buffer memory, right? If so, then you can't expect them to have ethtool included and their=20 developers are not likely to be happy over having to "waste" another=20 100KB in order to tune a 20KB driver. My vote goes for sysfs. /Lars