From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from alln-iport-5.cisco.com (alln-iport-5.cisco.com [173.37.142.92]) by dpdk.org (Postfix) with ESMTP id 927ABC660 for ; Sat, 25 Jun 2016 00:43:01 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=787; q=dns/txt; s=iport; t=1466808181; x=1468017781; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=5UzgI1yALIQ2oVQvUh1SaA062YsaleZfkDvh1df+Qfo=; b=OcEh4No3mwiofcJMB/GTFtVG60qcIcH6EjdwksRmgrMSFVOR3yTahX2d bwpn34RJQxtUxFwTO3FqDAcVti2ABQcMqrBlIj/o+z5ekgFFT0kYE2Ep9 WgPpi4FMxBlIE/VwAh1YcnUI0IVd5ORkNQZ8NvQq130fL5Fkt2YC9Vya/ Q=; X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: =?us-ascii?q?A0AoAgC2tm1X/4MNJK1cgz6BWbgSgg+Be?= =?us-ascii?q?4YYAoEvOBQBAQEBAQEBZSeETQEBBDo/EAIBCDYQMiUCBA4NiCjHGAEBAQEBAQE?= =?us-ascii?q?BAQEBAQEBAQEBAQEBHYYohE2KGwEEmQABjiyPKo99AR42g3CJH38BAQE?= X-IronPort-AV: E=Sophos;i="5.26,523,1459814400"; d="scan'208";a="287928492" Received: from alln-core-1.cisco.com ([173.36.13.131]) by alln-iport-5.cisco.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 24 Jun 2016 22:43:00 +0000 Received: from XCH-ALN-008.cisco.com (xch-aln-008.cisco.com [173.36.7.18]) by alln-core-1.cisco.com (8.14.5/8.14.5) with ESMTP id u5OMh0B0031313 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Fri, 24 Jun 2016 22:43:00 GMT Received: from xch-rcd-007.cisco.com (173.37.102.17) by XCH-ALN-008.cisco.com (173.36.7.18) with Microsoft SMTP Server (TLS) id 15.0.1104.5; Fri, 24 Jun 2016 17:42:59 -0500 Received: from xch-rcd-007.cisco.com ([173.37.102.17]) by XCH-RCD-007.cisco.com ([173.37.102.17]) with mapi id 15.00.1104.009; Fri, 24 Jun 2016 17:42:59 -0500 From: "John Daley (johndale)" To: Bruce Richardson CC: "dev@dpdk.org" Thread-Topic: [dpdk-dev] [PATCH 2/4] enic: set the max allowed MTU for the NIC Thread-Index: AQHRyFhM7V5frFJuo06eLpAVdcmvv5/40gqAgAAAfICAAGzjYA== Date: Fri, 24 Jun 2016 22:42:59 +0000 Message-ID: References: <1466140969-5580-1-git-send-email-johndale@cisco.com> <1466140969-5580-3-git-send-email-johndale@cisco.com> <20160624105919.GD13456@bricha3-MOBL3> <20160624110103.GE13456@bricha3-MOBL3> In-Reply-To: <20160624110103.GE13456@bricha3-MOBL3> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.24.18.14] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH 2/4] enic: set the max allowed MTU for the NIC X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jun 2016 22:43:01 -0000 Hi Bruce, > > * What was the MTU set to by default before this patch is applied? Was > > it just set to 1518 or something else? > > * What happens, if anything, if buffers bigger than the MTU size are se= nt > down? > This is obviously referring to buffers bigger than MTU on TX. There is al= so the > question of what happens if buffer sizes smaller than MTU are provided on > RX. I think I answered all your questions in the revised commit messages of the= v2 patchset (and then some) except this last one. Enic doesn't do any chec= king on Rx that buffers are greater than the MTU since it would affect perf= ormance. However if a packet is bigger than a buffer and Rx scatter is disa= bled, the packet will be dropped and 'imissed' incremented. Thanks, Johnd