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Date: Thu, 14 Nov 2013 17:17:51 +0400
From: Gleb Smirnoff <glebius@FreeBSD.org>
To: Luigi Rizzo <rizzo@iet.unipi.it>
Subject: Re: RFC: adding queue number/size fields to ifnet
Message-ID: <20131114131751.GI7577@FreeBSD.org>
References: <20131114110107.GA36421@onelab2.iet.unipi.it>
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On Thu, Nov 14, 2013 at 12:01:07PM +0100, Luigi Rizzo wrote:
L> Hi,
L> it would be useful to have a common place with the indication of
L> NIC parameters such as number of tx/rx queues and their lengths.
L> 
L> Various 10G drivers do include this information in various places
L> in the softc, but there is no common place.
L>  
L> I was wondering if there is any objection to either or both 
L> of these options:
L> 
L> 1. four fields to the struct ifnet (field names are bikeshed material
L>    and irrelevant for the discussion):
L>       if_tx_queues, if_rx_queues, if_tx_slots, if_rx_slots
L> 
L> 2. a sysctl-like get/set method for key-value pairs (key is always a
L>    string, value is possibly one of a few simple types such as
L>    INT64, UINT64, STRING) so that we extend the system in the future,
L>    e.g. to handle RSS, flow control and whatnot.
L>       Of course this also requires to settle on names of features.
L> 
L> This is meant for low-frequency access to the parameters of the
L> device, so performance is not an issue. 

The API for drivers to express to the stack their capabilities  is planned
to be implemented soon. Andre has grant from FF for that.

-- 
Totus tuus, Glebius.