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GET /api/patches/45586/?format=api
{ "id": 45586, "url": "https://patches.dpdk.org/api/patches/45586/?format=api", "web_url": "https://patches.dpdk.org/project/dpdk/patch/1538146714-30973-3-git-send-email-liang.j.ma@intel.com/", "project": { "id": 1, "url": "https://patches.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": "<1538146714-30973-3-git-send-email-liang.j.ma@intel.com>", "list_archive_url": "https://inbox.dpdk.org/dev/1538146714-30973-3-git-send-email-liang.j.ma@intel.com", "date": "2018-09-28T14:58:33", "name": "[v9,3/4] doc/guides/pro_guide/power-man: update the power API", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": true, "hash": "67c6a47c8cc9e5e7eddfb860a0832a975e3ea92d", "submitter": { "id": 904, "url": "https://patches.dpdk.org/api/people/904/?format=api", "name": "Liang, Ma", "email": "liang.j.ma@intel.com" }, "delegate": { "id": 1, "url": "https://patches.dpdk.org/api/users/1/?format=api", "username": "tmonjalo", "first_name": "Thomas", "last_name": "Monjalon", "email": "thomas@monjalon.net" }, "mbox": "https://patches.dpdk.org/project/dpdk/patch/1538146714-30973-3-git-send-email-liang.j.ma@intel.com/mbox/", "series": [ { "id": 1575, "url": "https://patches.dpdk.org/api/series/1575/?format=api", "web_url": "https://patches.dpdk.org/project/dpdk/list/?series=1575", "date": "2018-09-28T14:58:32", "name": "[v9,1/4] lib/librte_power: traffic pattern aware power control", "version": 9, "mbox": "https://patches.dpdk.org/series/1575/mbox/" } ], "comments": "https://patches.dpdk.org/api/patches/45586/comments/", "check": "success", "checks": "https://patches.dpdk.org/api/patches/45586/checks/", "tags": {}, "related": [], "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 E19001B4DF;\n\tFri, 28 Sep 2018 16:58:51 +0200 (CEST)", "from mga02.intel.com (mga02.intel.com [134.134.136.20])\n\tby dpdk.org (Postfix) with ESMTP id 7CFED1B4DE\n\tfor <dev@dpdk.org>; Fri, 28 Sep 2018 16:58:50 +0200 (CEST)", "from orsmga007.jf.intel.com ([10.7.209.58])\n\tby orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384;\n\t28 Sep 2018 07:58:49 -0700", "from irvmail001.ir.intel.com ([163.33.26.43])\n\tby orsmga007.jf.intel.com with ESMTP; 28 Sep 2018 07:58:48 -0700", "from sivswdev01.ir.intel.com (sivswdev01.ir.intel.com\n\t[10.237.217.45])\n\tby irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id\n\tw8SEwlrw016661; Fri, 28 Sep 2018 15:58:47 +0100", "from sivswdev01.ir.intel.com (localhost [127.0.0.1])\n\tby sivswdev01.ir.intel.com with ESMTP id w8SEwlTs031235;\n\tFri, 28 Sep 2018 15:58:47 +0100", "(from lma25@localhost)\n\tby sivswdev01.ir.intel.com with LOCAL id w8SEwlV5031231;\n\tFri, 28 Sep 2018 15:58:47 +0100" ], "X-Amp-Result": "SKIPPED(no attachment in message)", "X-Amp-File-Uploaded": "False", "X-ExtLoop1": "1", "X-IronPort-AV": "E=Sophos;i=\"5.54,315,1534834800\"; d=\"scan'208\";a=\"76883601\"", "From": "Liang Ma <liang.j.ma@intel.com>", "To": "david.hunt@intel.com", "Cc": "dev@dpdk.org, lei.a.yao@intel.com, ktraynor@redhat.com,\n\tmarko.kovacevic@intel.com, Liang Ma <liang.j.ma@intel.com>", "Date": "Fri, 28 Sep 2018 15:58:33 +0100", "Message-Id": "<1538146714-30973-3-git-send-email-liang.j.ma@intel.com>", "X-Mailer": "git-send-email 1.7.7.4", "In-Reply-To": "<1538146714-30973-1-git-send-email-liang.j.ma@intel.com>", "References": "<1537191016-26330-1-git-send-email-liang.j.ma@intel.com>\n\t<1538146714-30973-1-git-send-email-liang.j.ma@intel.com>", "Subject": "[dpdk-dev] [PATCH v9 3/4] doc/guides/pro_guide/power-man: update\n\tthe power API", "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": "Update the document for empty poll API.\n\nChange Logs:\nv9: minor changes for syntax. Update document.\n\nSigned-off-by: Liang Ma <liang.j.ma@intel.com>\n---\n doc/guides/prog_guide/power_man.rst | 86 +++++++++++++++++++++++++++++++++++++\n 1 file changed, 86 insertions(+)", "diff": "diff --git a/doc/guides/prog_guide/power_man.rst b/doc/guides/prog_guide/power_man.rst\nindex eba1cc6..68b7e8b 100644\n--- a/doc/guides/prog_guide/power_man.rst\n+++ b/doc/guides/prog_guide/power_man.rst\n@@ -106,6 +106,92 @@ User Cases\n \n The power management mechanism is used to save power when performing L3 forwarding.\n \n+\n+Empty Poll API\n+--------------\n+\n+Abstract\n+~~~~~~~~\n+\n+For packet processing workloads such as DPDK polling is continuous.\n+This means CPU cores always show 100% busy independent of how much work\n+those cores are doing. It is critical to accurately determine how busy\n+a core is hugely important for the following reasons:\n+\n+ * No indication of overload conditions\n+ * User does not know how much real load is on a system, resulting\n+ in wasted energy as no power management is utilized\n+\n+Compared to the original l3fwd-power design, instead of going to sleep\n+after detecting an empty poll, the new mechanism just lowers the core frequency.\n+As a result, the application does not stop polling the device, which leads\n+to improved handling of bursts of traffic.\n+\n+When the system become busy, the empty poll mechanism can also increase the core\n+frequency (including turbo) to do best effort for intensive traffic. This gives\n+us more flexible and balanced traffic awareness over the standard l3fwd-power\n+application.\n+\n+\n+Proposed Solution\n+~~~~~~~~~~~~~~~~~\n+The proposed solution focuses on how many times empty polls are executed.\n+The less the number of empty polls, means current core is busy with processing\n+workload, therefore, the higher frequency is needed. The high empty poll number\n+indicates the current core not doing any real work therefore, we can lower the\n+frequency to safe power.\n+\n+In the current implementation, each core has 1 empty-poll counter which assume\n+1 core is dedicated to 1 queue. This will need to be expanded in the future to\n+support multiple queues per core.\n+\n+Power state definition:\n+^^^^^^^^^^^^^^^^^^^^^^^\n+\n+* LOW: Not currently used, reserved for future use.\n+\n+* MED: the frequency is used to process modest traffic workload.\n+\n+* HIGH: the frequency is used to process busy traffic workload.\n+\n+There are two phases to establish the power management system:\n+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n+* Training phase. This phase is used to measure the optimal frequency\n+ change thresholds for a given system. The thresholds will differ from\n+ system to system due to differences in processor micro-architecture,\n+ cache and device configurations.\n+ In this phase, the user must ensure that no traffic can enter the\n+ system so that counts can be measured for empty polls at low, medium\n+ and high frequencies. Each frequency is measured for two seconds.\n+ Once the training phase is complete, the threshold numbers are\n+ displayed, and normal mode resumes, and traffic can be allowed into\n+ the system. These threshold number can be used on the command line\n+ when starting the application in normal mode to avoid re-training\n+ every time.\n+\n+* Normal phase. Every 10ms the run-time counters are compared\n+ to the supplied threshold values, and the decision will be made\n+ whether to move to a different power state (by adjusting the\n+ frequency).\n+\n+API Overview for Empty Poll Power Management\n+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n+* **State Init**: initialize the power management system.\n+\n+* **State Free**: free the resource hold by power management system.\n+\n+* **Update Empty Poll Counter**: update the empty poll counter.\n+\n+* **Update Valid Poll Counter**: update the valid poll counter.\n+\n+* **Set the Fequence Index**: update the power state/frequency mapping.\n+\n+* **Detect empty poll state change**: empty poll state change detection algorithm then take action.\n+\n+User Cases\n+----------\n+The mechanism can applied to any device which is based on polling. e.g. NIC, FPGA.\n+\n References\n ----------\n \n", "prefixes": [ "v9", "3/4" ] }