From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id DA8DDA04F3; Fri, 6 Dec 2019 21:37:07 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 1B44B1BEDE; Fri, 6 Dec 2019 21:37:07 +0100 (CET) Received: from mail.lysator.liu.se (mail.lysator.liu.se [130.236.254.3]) by dpdk.org (Postfix) with ESMTP id 00FFC4C9D for ; Fri, 6 Dec 2019 21:37:05 +0100 (CET) Received: from mail.lysator.liu.se (localhost [127.0.0.1]) by mail.lysator.liu.se (Postfix) with ESMTP id 6E47A40018 for ; Fri, 6 Dec 2019 21:37:03 +0100 (CET) Received: by mail.lysator.liu.se (Postfix, from userid 1004) id 4B7934000A; Fri, 6 Dec 2019 21:37:03 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on bernadotte.lysator.liu.se X-Spam-Level: X-Spam-Status: No, score=-0.0 required=5.0 tests=ALL_TRUSTED,AWL autolearn=disabled version=3.4.2 X-Spam-Score: -0.0 Received: from [192.168.1.59] (host-95-205-107-14.mobileonline.telia.com [95.205.107.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.lysator.liu.se (Postfix) with ESMTPSA id 82FE34000A; Fri, 6 Dec 2019 21:37:02 +0100 (CET) To: Venky Venkatesh Cc: dev@dpdk.org References: <9e58e2a0-0a6a-4dec-ffe7-e9ea7cf33099@ericsson.com> From: =?UTF-8?Q?Mattias_R=c3=b6nnblom?= Message-ID: Date: Fri, 6 Dec 2019 21:37:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP Subject: Re: [dpdk-dev] eventdev DSW question 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: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 2019-12-06 17:32, Venky Venkatesh wrote: > Thanks Mattias for the clarifications. > > 1 more question: This time it is about the inflight accounting for DSW. > Here is my understanding: it seems to consider only the events which > are *inside > the scheduler* as in flight. Yes, like all event devices, I believe. > I am trying to distinguish it from those which > have been currently given to cores by the scheduler. The latter are not > considered in flight since we dsw_port_return_credits as soon as > dsw_event_dequeue_burst. A new dequeue means an implicit release of all unreleased events dequeued in the previous call. It's standard Eventdev semantics. > So if these events which are in core currently do > a FORWARD, there is a chance that those can fail. Ideally those FORWARDs > should not fail -- which can happen with the current design as some NEWs > can hog those credits freed up by the ones which have been dequeued by > cores. What you do to avoid this situation is set the new_event_threshold low-enough, so NEW events don't block FORWARDed ones. > Is this design of DSW intentional or an omission? If it is an > omission I can work on a possible fix and run it by you. > This is not really a DSW design, but rather how Eventdev works.