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{ "id": 59380, "url": "http://patchwork.dpdk.org/api/covers/59380/?format=api", "web_url": "http://patchwork.dpdk.org/project/dpdk/cover/20190919163643.24130-1-yong.liu@intel.com/", "project": { "id": 1, "url": "http://patchwork.dpdk.org/api/projects/1/?format=api", "name": "DPDK", "link_name": "dpdk", "list_id": "dev.dpdk.org", "list_email": "dev@dpdk.org", "web_url": "http://core.dpdk.org", "scm_url": "git://dpdk.org/dpdk", "webscm_url": "http://git.dpdk.org/dpdk", "list_archive_url": "https://inbox.dpdk.org/dev", "list_archive_url_format": "https://inbox.dpdk.org/dev/{}", "commit_url_format": "" }, "msgid": "<20190919163643.24130-1-yong.liu@intel.com>", "list_archive_url": "https://inbox.dpdk.org/dev/20190919163643.24130-1-yong.liu@intel.com", "date": "2019-09-19T16:36:27", "name": "[v2,00/16] vhost packed ring performance optimization", "submitter": { "id": 17, "url": "http://patchwork.dpdk.org/api/people/17/?format=api", "name": "Marvin Liu", "email": "yong.liu@intel.com" }, "mbox": "http://patchwork.dpdk.org/project/dpdk/cover/20190919163643.24130-1-yong.liu@intel.com/mbox/", "series": [ { "id": 6444, "url": "http://patchwork.dpdk.org/api/series/6444/?format=api", "web_url": "http://patchwork.dpdk.org/project/dpdk/list/?series=6444", "date": "2019-09-19T16:36:27", "name": "vhost packed ring performance optimization", "version": 2, "mbox": "http://patchwork.dpdk.org/series/6444/mbox/" } ], "comments": "http://patchwork.dpdk.org/api/covers/59380/comments/", "headers": { "Return-Path": "<dev-bounces@dpdk.org>", "X-Original-To": "patchwork@dpdk.org", "Delivered-To": "patchwork@dpdk.org", "Received": [ "from [92.243.14.124] (localhost [127.0.0.1])\n\tby dpdk.org (Postfix) with ESMTP id 2927D1C1BD;\n\tThu, 19 Sep 2019 10:56:25 +0200 (CEST)", "from mga14.intel.com (mga14.intel.com [192.55.52.115])\n\tby dpdk.org (Postfix) with ESMTP id 5F6511C1B8\n\tfor <dev@dpdk.org>; Thu, 19 Sep 2019 10:56:24 +0200 (CEST)", "from orsmga001.jf.intel.com ([10.7.209.18])\n\tby fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384;\n\t19 Sep 2019 01:56:23 -0700", "from npg-dpdk-virtual-marvin-dev.sh.intel.com ([10.67.119.142])\n\tby orsmga001.jf.intel.com with ESMTP; 19 Sep 2019 01:56:21 -0700" ], "X-Amp-Result": "SKIPPED(no attachment in message)", "X-Amp-File-Uploaded": "False", "X-ExtLoop1": "1", "X-IronPort-AV": "E=Sophos;i=\"5.64,523,1559545200\"; d=\"scan'208\";a=\"271146069\"", "From": "Marvin Liu <yong.liu@intel.com>", "To": "maxime.coquelin@redhat.com, tiwei.bie@intel.com, zhihong.wang@intel.com", "Cc": "dev@dpdk.org,\n\tMarvin Liu <yong.liu@intel.com>", "Date": "Fri, 20 Sep 2019 00:36:27 +0800", "Message-Id": "<20190919163643.24130-1-yong.liu@intel.com>", "X-Mailer": "git-send-email 2.17.1", "In-Reply-To": "<20190905161421.55981-2-yong.liu@intel.com>", "References": "<20190905161421.55981-2-yong.liu@intel.com>", "MIME-Version": "1.0", "Content-Type": "text/plain; charset=UTF-8", "Content-Transfer-Encoding": "8bit", "Subject": "[dpdk-dev] [PATCH v2 00/16] vhost packed ring performance\n\toptimization", "X-BeenThere": "dev@dpdk.org", "X-Mailman-Version": "2.1.15", "Precedence": "list", "List-Id": "DPDK patches and discussions <dev.dpdk.org>", "List-Unsubscribe": "<https://mails.dpdk.org/options/dev>,\n\t<mailto:dev-request@dpdk.org?subject=unsubscribe>", "List-Archive": "<http://mails.dpdk.org/archives/dev/>", "List-Post": "<mailto:dev@dpdk.org>", "List-Help": "<mailto:dev-request@dpdk.org?subject=help>", "List-Subscribe": "<https://mails.dpdk.org/listinfo/dev>,\n\t<mailto:dev-request@dpdk.org?subject=subscribe>", "Errors-To": "dev-bounces@dpdk.org", "Sender": "\"dev\" <dev-bounces@dpdk.org>" }, "content": "Packed ring has more compact ring format and thus can significantly\nreduce the number of cache miss. It can lead to better performance.\nThis has been approved in virtio user driver, on normal E5 Xeon cpu\nsingle core performance can raise 12%.\n\nhttp://mails.dpdk.org/archives/dev/2018-April/095470.html\n\nHowever vhost performance with packed ring performance was decreased.\nThrough analysis, mostly extra cost was from the calculating of each\ndescriptor flag which depended on ring wrap counter. Moreover, both\nfrontend and backend need to write same descriptors which will cause\ncache contention. Especially when doing vhost enqueue function, virtio\nrefill packed ring function may write same cache line when vhost doing\nenqueue function. This kind of extra cache cost will reduce the benefit\nof reducing cache misses. \n\nFor optimizing vhost packed ring performance, vhost enqueue and dequeue\nfunction will be splitted into fast and normal path.\n\nSeveral methods will be taken in fast path:\n Uroll burst loop function into more pieces.\n Handle descriptors in one cache line simultaneously.\n Prerequisite check that whether I/O space can copy directly into mbuf\n space and vice versa. \n Prerequisite check that whether descriptor mapping is successful.\n Distinguish vhost used ring update function by enqueue and dequeue\n function.\n Buffer dequeue used descriptors as many as possible.\n Update enqueue used descriptors by cache line.\n Cache memory region structure for fast conversion.\n Disable sofware prefetch is hardware can do better.\n\nAfter all these methods done, single core vhost PvP performance with 64B\npacket on Xeon 8180 can boost 40%.\n\nv2:\n- Utilize compiler's pragma to unroll loop, distinguish clang/icc/gcc\n- Buffered dequeue used desc number changed to (RING_SZ - PKT_BURST)\n- Optimize dequeue used ring update when in_order negotiated\n\nMarvin Liu (16):\n vhost: add single packet enqueue function\n vhost: unify unroll pragma parameter\n vhost: add burst enqueue function for packed ring\n vhost: add single packet dequeue function\n vhost: add burst dequeue function\n vhost: rename flush shadow used ring functions\n vhost: flush vhost enqueue shadow ring by burst\n vhost: add flush function for burst enqueue\n vhost: buffer vhost dequeue shadow ring\n vhost: split enqueue and dequeue flush functions\n vhost: optimize enqueue function of packed ring\n vhost: add burst and single zero dequeue functions\n vhost: optimize dequeue function of packed ring\n vhost: cache address translation result\n vhost: check whether disable software pre-fetch\n vhost: optimize packed ring dequeue when in-order\n\n lib/librte_vhost/Makefile | 24 +\n lib/librte_vhost/rte_vhost.h | 27 +\n lib/librte_vhost/vhost.h | 33 +\n lib/librte_vhost/virtio_net.c | 1071 +++++++++++++++++++++++++++------\n 4 files changed, 960 insertions(+), 195 deletions(-)" }