From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [PATCH 1/3] ethdev: add max burst size to device info
Date: Wed, 23 May 2018 00:17:13 +0200
Message-ID: <1867579.zxL6BAlCOx@xps>
References: <20171212100520.20502-1-nikhil.agarwal@linaro.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7Bit
Cc: dev@dpdk.org, david.hunt@intel.com, nikhil.agarwal@nxp.com,
 hemant.agrawal@nxp.com, ferruh.yigit@intel.com, arybchenko@solarflare.com,
 shahafs@mellanox.com
To: Nikhil Agarwal <nikhil.agarwal@linaro.org>
Return-path: <dev-bounces@dpdk.org>
Received: from out3-smtp.messagingengine.com (out3-smtp.messagingengine.com
 [66.111.4.27]) by dpdk.org (Postfix) with ESMTP id 89DA71D9E
 for <dev@dpdk.org>; Wed, 23 May 2018 00:17:16 +0200 (CEST)
In-Reply-To: <20171212100520.20502-1-nikhil.agarwal@linaro.org>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://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: <https://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

12/12/2017 11:05, Nikhil Agarwal:
> Currently, if the  rte_eth_rx_burst() function returns a value less than
> *nb_pkts*, the application will assume that no more packets are present.
> 
> Some of the hw queue based hardware can only support smaller burst for RX
> and TX and thus break the expectation of the rx_burst API.
> 
> This patch adds support to provide the maximum burst size that can be
> supported by a given PMD. The dev_info is being memset to '0' in
> rte_ethdev library. The value of '0' indicates that any value for burst
> size can be supported i.e. no change for existing PMDs.
> 
> The application can now use the lowest available max_burst_size value
> for rte_eth_rx_burst.
> 
> Signed-off-by: Nikhil Agarwal <nikhil.agarwal@linaro.org>
> ---
> @@ -1047,6 +1047,7 @@ struct rte_eth_dev_info {
>  	/** Configured number of rx/tx queues */
>  	uint16_t nb_rx_queues; /**< Number of RX queues. */
>  	uint16_t nb_tx_queues; /**< Number of TX queues. */
> +	uint16_t max_burst_size; /**< MAX burst size, 0 for no limit. */
>  };

What is the status of this proposal?

Recently, the preferred tuning have been added by
	"ethdev: support PMD-tuned Tx/Rx parameters"
	http://dpdk.org/commit/3be82f5cc5