From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 52B7E1B21B for ; Wed, 1 Nov 2017 03:03:37 +0100 (CET) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Oct 2017 19:03:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,326,1505804400"; d="scan'208";a="170295986" Received: from fmsmsx103.amr.corp.intel.com ([10.18.124.201]) by fmsmga006.fm.intel.com with ESMTP; 31 Oct 2017 19:03:36 -0700 Received: from fmsmsx158.amr.corp.intel.com (10.18.116.75) by FMSMSX103.amr.corp.intel.com (10.18.124.201) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 31 Oct 2017 19:03:36 -0700 Received: from shsmsx152.ccr.corp.intel.com (10.239.6.52) by fmsmsx158.amr.corp.intel.com (10.18.116.75) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 31 Oct 2017 19:03:36 -0700 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.175]) by SHSMSX152.ccr.corp.intel.com ([169.254.6.93]) with mapi id 14.03.0319.002; Wed, 1 Nov 2017 10:03:33 +0800 From: "Lu, Wenzhuo" To: "Richardson, Bruce" CC: "dev@dpdk.org" Thread-Topic: [dpdk-dev] [PATCH v2] doc: more clarification for i40e 16 bytes desc Thread-Index: AQHTUfnbq9RliSpZSUOL00W6+JGXSqL9NRUAgAGR7XA= Date: Wed, 1 Nov 2017 02:03:33 +0000 Message-ID: <6A0DE07E22DDAD4C9103DF62FEBC09093B6DB5A1@shsmsx102.ccr.corp.intel.com> References: <1508900093-9894-1-git-send-email-wenzhuo.lu@intel.com> <1509421233-81295-1-git-send-email-wenzhuo.lu@intel.com> <20171031100400.GA10572@bricha3-MOBL3.ger.corp.intel.com> In-Reply-To: <20171031100400.GA10572@bricha3-MOBL3.ger.corp.intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v2] doc: more clarification for i40e 16 bytes desc X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Nov 2017 02:03:38 -0000 Hi Bruce, > -----Original Message----- > From: Richardson, Bruce > Sent: Tuesday, October 31, 2017 6:04 PM > To: Lu, Wenzhuo > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH v2] doc: more clarification for i40e 16 by= tes > desc >=20 > On Tue, Oct 31, 2017 at 11:40:33AM +0800, Wenzhuo Lu wrote: > > The description of i40e 16 bytes descriptor is not clear enough. Add > > more details. > > > > Signed-off-by: Wenzhuo Lu >=20 > Thanks for the clarification, it's better now. Couple of minor tweaks I w= ould > suggest below. >=20 > Otherwise: > Acked-by: Bruce Richardson >=20 > > --- > > doc/guides/nics/i40e.rst | 21 ++++++++++++++++----- > > 1 file changed, 16 insertions(+), 5 deletions(-) > > > > diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst index > > a0946e6..771620c 100644 > > --- a/doc/guides/nics/i40e.rst > > +++ b/doc/guides/nics/i40e.rst > > @@ -398,13 +398,24 @@ used to classify MPLS packet by using a command > in testpmd like: > > testpmd> ethertype_filter 0 add mac_ignr 00:00:00:00:00:00 ethertyp= e \ > > 0x8847 fwd queue > > > > -16 Byte Descriptor cannot be used on DPDK VF > > -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > +16 Bytes Descriptor setting on DPDK VF > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >=20 > We tend to refer to these as "16-byte" and "32-byte" descriptors in the > singular, not "16-bytes". >=20 > > > > +Currently the VF's RX descriptor mode is decided by PF. There's no > > +PF-VF interface for VF to request the RX descriptor mode, also no > > +interface to nofify VF its own RX descriptor mode. > > +Until i40e 2.1.26, the Linux i40e driver doesn't support 16 bytes RX > descriptor. >=20 > This implies that the 2.1.26 driver does support setting the descriptor s= ize, > though later text implies that this is not the case. > Therefore, I suggest changing "Until i40e 2.1.26", to "For all available > versions of the i40e driver," and omit the version number, since it will = soon > be out of date otherwise. The only time we should need to update this is > when/if there is a kernel version that does support reporting or seting t= he > descriptor size. Thanks for the review and comments. I'll send a V3 and add your ack :) >=20 > > If the Linux i40e kernel driver is used as host driver, while DPDK > > i40e PMD -is used as the VF driver, DPDK cannot choose 16 byte receive > > descriptor. That -is to say, user should keep > > ``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC=3Dn`` in -config file. > > +is used as the VF driver, DPDK cannot choose 16 byte receive > > +descriptor. The reason is that the RX descriptor is already set to 32 > > +bytes by the i40e kernel driver. That is to say, user should keep > > +``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC=3Dn`` in config file. > > +In the future, if the Linux i40e driver supports 16 bytes RX > > +descriptor, user should make sure the DPDK VF uses the same RX > > +descriptor mode, 16 bytes or 32 bytes, as the PF driver. > > + > > +The same rule for DPDK PF + DPDK VF. The PF and VF should use the > > +same RX descriptor mode. Or the VF RX will not work. > > > > Receive packets with Ethertype 0x88A8 > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > -- > > 1.9.3 > >