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 A66C637A4 for ; Sun, 22 Mar 2015 14:25:11 +0100 (CET) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP; 22 Mar 2015 06:25:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,446,1422950400"; d="scan'208";a="470879044" Received: from irvmail001.ir.intel.com ([163.33.26.43]) by FMSMGA003.fm.intel.com with ESMTP; 22 Mar 2015 06:25:09 -0700 Received: from sivswdev02.ir.intel.com (sivswdev02.ir.intel.com [10.237.217.46]) by irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id t2MDP8Ym012700; Sun, 22 Mar 2015 13:25:08 GMT Received: from sivswdev02.ir.intel.com (localhost [127.0.0.1]) by sivswdev02.ir.intel.com with ESMTP id t2MDP8fO006126; Sun, 22 Mar 2015 13:25:08 GMT Received: (from sabutler@localhost) by sivswdev02.ir.intel.com with id t2MDP8Ke006122; Sun, 22 Mar 2015 13:25:08 GMT From: Siobhan Butler To: dev@dpdk.org Date: Sun, 22 Mar 2015 13:25:07 +0000 Message-Id: <1427030707-6091-1-git-send-email-siobhan.a.butler@intel.com> X-Mailer: git-send-email 1.7.4.1 Subject: [dpdk-dev] [PATCH] doc: added to faq section of release notes 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: Sun, 22 Mar 2015 13:25:12 -0000 Added some of the questions posted to the mailing list to the FAQ section of release notes. Signed-off-by: Siobhan Butler --- doc/guides/rel_notes/faq.rst | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/doc/guides/rel_notes/faq.rst b/doc/guides/rel_notes/faq.rst index 054db10..14b1167 100644 --- a/doc/guides/rel_notes/faq.rst +++ b/doc/guides/rel_notes/faq.rst @@ -191,3 +191,38 @@ In this case, this has to be done manually on the VM host, using the following c where being the interface providing the virtual functions for example, eth0, being the virtual function number, for example 0, and being the desired MAC address. + +Is it safe to add an entry to the hash table while running? +------------------------------------------------------------ +Currently the table implementation is not a thread safe implementation and assumes that locking between threads and processes is handled by the user's application. +This is likely to be supported in future releases. + +What is the purpose of setting iommu=pt? +---------------------------------------- +DPDK uses a 1:1 mapping and does not support IOMMU. IOMMU allows for simpler VM physical address translation. +The second role of IOMMU is to allow protection from unwanted memory access by an unsafe device that has DMA privileges. +Unfortunately, the protection comes with an extremely high perfomance cost for high speed NICs. + +iommu=pt disables IOMMU support for the hypervisor. + +When trying to send packets from an application to itself, meaning smac==dmac, using Intel(R) 82599 VF packets are lost. +------------------------------------------------------------------------------------------------------------------------ +Check on register LLE(PFVMTXSSW[n]), which allows an individual pool to send traffic and have it looped back to itself. + +Can I split packet RX to use DPDK and have an application's higher order functions continue using Linux* pthread? +----------------------------------------------------------------------------------------------------------------- +The DPDK's lcore threads are Linux* pthreads bound onto specific cores. Configure the DPDK to do work on the same +cores and run the application's other work on other cores using the DPDK's "coremask" setting to specify which +cores it should launch itself on. + +Is it possible to exchange data between DPDK processes and regular userspace processes via some shared memory or IPC mechanism? +------------------------------------------------------------------------------------------------------------------------------- +Yes - DPDK processes are regular Linux/BSD processes, and can use all OS provided IPC mechanisms. + +Can the multiple queues in Intel(R) I350 be used with DPDK? +----------------------------------------------------------- +I350 has RSS support and 8 queue pairs can be used in RSS mode. It should work with multi-queue DPDK applications using RSS. + +How can hugepage-backed memory be shared among multiple processes? +------------------------------------------------------------------ +See the Primary and Secondary examples in the multi-process sample application. -- 1.8.3.1