From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id 3A18C3238 for ; Tue, 21 Feb 2017 11:28:04 +0100 (CET) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Feb 2017 02:28:03 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,189,1484035200"; d="scan'208";a="1132774871" Received: from irsmsx102.ger.corp.intel.com ([163.33.3.155]) by fmsmga002.fm.intel.com with ESMTP; 21 Feb 2017 02:28:02 -0800 Received: from irsmsx105.ger.corp.intel.com ([169.254.7.38]) by IRSMSX102.ger.corp.intel.com ([169.254.2.230]) with mapi id 14.03.0248.002; Tue, 21 Feb 2017 10:28:01 +0000 From: "Ananyev, Konstantin" To: Olivier MATZ CC: Jan Blunck , "dev@dpdk.org" Thread-Topic: [dpdk-dev] [RFC 0/8] mbuf: structure reorganization Thread-Index: AQHSdlXOvL8VQlbyOU+/T85mDKip26FcYNGAgA9pHoCAAD0PgIABJAiAgAAukACAAArJAIAASJ3ggAW3JICAAAf5gA== Date: Tue, 21 Feb 2017 10:28:00 +0000 Message-ID: <2601191342CEEE43887BDE71AB9772583F119F91@irsmsx105.ger.corp.intel.com> References: <1485271173-13408-1-git-send-email-olivier.matz@6wind.com> <2601191342CEEE43887BDE71AB9772583F111A29@irsmsx105.ger.corp.intel.com> <20170216144807.7add2c71@platinum> <20170217115153.0afeb061@platinum> <20170217151708.20bf4a49@platinum> <2601191342CEEE43887BDE71AB9772583F118DD7@irsmsx105.ger.corp.intel.com> <20170221105349.1fb36287@glumotte.dev.6wind.com> In-Reply-To: <20170221105349.1fb36287@glumotte.dev.6wind.com> Accept-Language: en-IE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [RFC 0/8] mbuf: structure reorganization 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: Tue, 21 Feb 2017 10:28:04 -0000 Hi Olivier, > -----Original Message----- > From: Olivier MATZ [mailto:olivier.matz@6wind.com] > Sent: Tuesday, February 21, 2017 9:54 AM > To: Ananyev, Konstantin > Cc: Olivier Matz ; Jan Blunck ; dev@dpdk.org > Subject: Re: [dpdk-dev] [RFC 0/8] mbuf: structure reorganization >=20 > Hi Konstantin, >=20 > On Fri, 17 Feb 2017 18:42:01 +0000, "Ananyev, Konstantin" > wrote: > > Hi guys, > > > > > > My point is that I still doubt that it belongs into the first > > > > cacheline. It requires accessing other structures for converting > > > > into nanoseconds anyway. Optimally I would like to see this > > > > happening on access instead but if that isn't achievable at least > > > > in a second step. > > > > > > Sorry, I don't really get your point. My comprehension of the > > > timestamp usage in a PMD is as following: > > > > > > rx_burst(struct rxq *rxq, ...) > > > { > > > unsigned long factor =3D rxq->timestamp_factor; > > > unsigned port =3D rxq->port; > > > > > > for each hw_desc { > > > m =3D rte_pktmbuf_alloc(rxq->pool); > > > m->len =3D hw_desc->len; > > > m->port =3D port; > > > m->ol_flags =3D > > > ... > > > m->timestamp =3D hw_desc->timestamp * factor; > > > } > > > ... > > > } > > > > > > In that case, I think it deserves to be in the 1st cache line. > > > > So you are saying that: > > - for some HW that DPDK supports (mlx?) timestamp information > > Is available in HW RX descriptor > > - and as soon timestamp field will be available in mbuf, you plan > > to populate it using this HW RXD field. > > Is that so? >=20 > Yes, that's what I'm seeing in mellanox's patchset: > http://dpdk.org/ml/archives/dev/2016-October/048810.html Have to admit that I saw that patch before, but missed the fact that timestamp value is taken from HW RXD. Ok, then I suppose I don't' have any good reason to object against putting it in the first cache-line. >=20 > Do you know if Intel has plans to support some sort of timestamp using > this timestamp field? >=20 As I remember, metrics library uses it, but right now it is filled by SW. Konstantin