From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Sanford, Robert" <rsanford@akamai.com>
Subject: Ethernet API - multiple post-RX-burst callbacks'
 run-order is opposite to their add-order
Date: Thu, 2 Jul 2015 21:04:48 +0000
Message-ID: <D1BB0052.A7DB%rsanford@akamai.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
To: "Richardson, Bruce" <bruce.richardson@intel.com>, Thomas Monjalon
 <thomas.monjalon@6wind.com>, "dev@dpdk.org" <dev@dpdk.org>
Return-path: <dev-bounces@dpdk.org>
Received: from prod-mail-xrelay02.akamai.com (prod-mail-xrelay02.akamai.com
 [72.246.2.14]) by dpdk.org (Postfix) with ESMTP id 4F31C11F5
 for <dev@dpdk.org>; Thu,  2 Jul 2015 23:04:51 +0200 (CEST)
Content-Language: en-US
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

When one adds multiple post-RX-burst callbacks to a queue, their execution =
order is the opposite of the order in which they are added. For example, we=
 add callback A( ), and then we add callback B( ). When we call rte_eth_rx_=
burst, after invoking the device's rx_pkt_burst function, it will invoke B(=
 ), and then A( ). The same goes for pre-TX-burst callbacks, too.

This is counter-intuitive. Shouldn't we either execute the callbacks in the=
 same order that we add them (by changing the internals of the add-APIs), o=
r change the add-APIs to allow one to specify whether a callback is added t=
o the head or tail of the callback list? At the least, we could document th=
e expected behavior.
Any thoughts on this?

--
Regards,
Robert