From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 534211B39A for ; Thu, 22 Nov 2018 11:05:42 +0100 (CET) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Nov 2018 02:05:41 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,265,1539673200"; d="scan'208";a="91279568" Received: from klaatz-mobl.ger.corp.intel.com (HELO [10.237.220.111]) ([10.237.220.111]) by orsmga007.jf.intel.com with ESMTP; 22 Nov 2018 02:05:39 -0800 To: Ferruh Yigit , Hideyuki Yamashita , dev@dpdk.org Cc: Harry Van Haaren , Bruce Richardson References: <201811210749.wAL7nrKg027704@ccmail04.silk.ntt-tx.co.jp> From: "Laatz, Kevin" Message-ID: <874cfe7e-e48f-ff90-9ad3-f57521386ec7@intel.com> Date: Thu, 22 Nov 2018 10:05:38 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Subject: Re: [dpdk-dev] Question about telemetry on 18.11 release 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: Thu, 22 Nov 2018 10:05:42 -0000 On 21/11/2018 11:38, Ferruh Yigit wrote: > On 11/21/2018 7:48 AM, Hideyuki Yamashita wrote: >> Hello, >> >> I have some basic questions about telemetry API >> which is planned to be relaesed in 18.11. >> >> Note that I have read the follwoing document. >> https://doc.dpdk.org/guides/howto/telemetry.html >> >> Q1. In general dpdk application use polling when >> receiving packets. So CPU usage is always looks 100% >> when measured using e.g. vmstat even if there is no packet receiving. >> (CPU is busy for polling packets) >> Is that correct? This is a general DPDK question and not specific to telemetry. The above is correct, it will always show as 100% busy. >> >> Q2. Is it correct understanding that dpdk application >> can send "any" value(or metric) to client if client >> requested via "telemetry" framework? Correct, assuming the metrics are being collected in the metrics library. The telemetry library grabs everything in the metrics library and sends it to the client. If an application exposes its metrics to the metrics library, then telemetry can pick this up. >> >> Q3.Is it possible to query "real cpu usage" from dpdk >> application using "telemetry" framework? >> ("real cpu usage" I mean if 0 pakcket incoming, >> cpu usage indicates almost 0 %) In short, no. The telemetry library only exposes what is available in the metrics library. Getting the "real DPDK cpu usage" is very difficult in general. >> >> Q4. Is it possible to inform client about fault or some >> trouble from dpdk application? Telemetry can provide the metrics but doesn't have any monitoring capabilities in terms of alerting the client of, let's say, an enormous burst of dropped packets. The telemetry library is purely a mechanism to transport metrics from DPDK to an external client. It is up to the client to interpret these metrics. >> >> Background I ask above is that >> - I am relative new to DPDK world and have almost no knowledge about >> "telemetry" >> - I am interested in how dpdk applications can "scales" on platform >> like OpenStack. I think some mesurement mechanism required >> and I thought it might be "telemetry" APIs. > Briefly I think yes, telemetry can be measurement mechanism and interface to > external application. Cc'ed Harry & Kevin for more detailed answers. > >> Thanks in advance. >> >> BR, >> Hideyuki Yamashita >> NTT TechnoCross >> >>