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From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
To: Beilei Xing <beilei.xing@intel.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: Feifei Wang <Feifei.Wang2@arm.com>,
	Ruifeng Wang <Ruifeng.Wang@arm.com>,
	Ferruh Yigit <ferruh.yigit@intel.com>,
	"bruce.richardson@intel.com" <bruce.richardson@intel.com>,
	nd <nd@arm.com>, nd <nd@arm.com>
Subject: Questions on i40e TX path
Date: Wed, 9 Feb 2022 04:35:53 +0000	[thread overview]
Message-ID: <AM8PR08MB5810B8B8615EF46442908093982E9@AM8PR08MB5810.eurprd08.prod.outlook.com> (raw)

Hi Beilei,
	I want to make sure my understanding of the TX path is correct. Following is my understanding.

1) The RS bit must be set in the TX descriptors to ask the NIC to report back the send status.
2) The NIC reports the send completion by setting the DTYPE field to 0xf. This also indicates that all the earlier descriptors are also done sending the packets.
3) The check "if (txq->nb_tx_free < txq->tx_free_thresh)" is mainly to ensure that we do not check the "descriptor done" status too often.

Is my understanding correct?

Thank you,
Honnappa

             reply	other threads:[~2022-02-09  4:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-09  4:35 Honnappa Nagarahalli [this message]
2022-02-09  7:58 ` Xing, Beilei
2022-02-10  4:37   ` Honnappa Nagarahalli
2022-02-11  2:33     ` Xing, Beilei
2022-02-11  4:07       ` Honnappa Nagarahalli

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