From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 62F0741B9E; Wed, 1 Feb 2023 12:20:36 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 4020142D12; Wed, 1 Feb 2023 12:20:36 +0100 (CET) Received: from agw.arknetworks.am (agw.arknetworks.am [79.141.165.80]) by mails.dpdk.org (Postfix) with ESMTP id A37D242D0E for ; Wed, 1 Feb 2023 12:20:34 +0100 (CET) Received: from debian (unknown [78.109.71.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by agw.arknetworks.am (Postfix) with ESMTPSA id 7F132E0162; Wed, 1 Feb 2023 15:20:33 +0400 (+04) Date: Wed, 1 Feb 2023 15:20:44 +0400 (+04) From: Ivan Malov To: Thomas Monjalon cc: Jerin Jacob , Andrew Rybchenko , Ferruh Yigit , Ori Kam , Nithin Kumar Dabilpuram , Aman Singh , Yuying Zhang , "dev@dpdk.org" , Hanumanth Reddy Pothula , Slava Ovsiienko , Jerin Jacob Kollanukkaran , "david.marchand@redhat.com" Subject: Re: [EXT] Re: [PATCH v5 2/2] app/testpmd: add command to process Rx metadata negotiation In-Reply-To: <2490780.4XsnlVU6TS@thomas> Message-ID: References: <20221220200250.2413443-1-hpothula@marvell.com> <98a80c20-a5e4-deea-f7dc-c6aa5d52800b@oktetlabs.ru> <2490780.4XsnlVU6TS@thomas> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Hi Thomas, On Wed, 1 Feb 2023, Thomas Monjalon wrote: > 01/02/2023 11:58, Andrew Rybchenko: >> On 2/1/23 13:48, Jerin Jacob wrote: >>> On Wed, Feb 1, 2023 at 2:59 PM Andrew Rybchenko >>> wrote: >>>> Frankly speaking I don't understand why default value is so >>>> important if we have a way to change it. Reasons should be >>>> really strong to change existing defaults. >>> >>> The only reason is, typically testpmd will be used performance >>> benchmarking as an industry standard. It is difficult to tell/educate >>> the QA or customers >>> that, "BTW if you need to get better performance add more flag to >>> testpmd command line". > > I disagree. > When you do performance benchmark, you tune settings accordingly. > >>> To make that worst, only some PMD needs to give the additional >>> parameter to get better number. >>> And also, testpmd usage will be treated as application modeling. >>> >>> Since this feature only used on sfc and cnxk driver, What is the >>> situation with sfc driver? >>> Keeping it as negotiated and not use the feature, will impact the per >>> core performance of sfc or >>> is it just PCI bandwidth thing which really dont show any difference in testpmd? >> >> Yes, sfc could run faster if no Rx metadata are negotiated. So, >> it is better to negotiate nothing by default. But it is always >> painful to change defaults. You need to explain that now you >> need to negotiate Rx metadata to use mark, flag and tunnel offloads. >> Yes, it will be required on sfc and cnxk only. >> As an sfc maintainer I don't mind to change testpmd defaults. > > If we change testpmd defaults to "do nothing", > then we should disable MBUF_FAST_FREE as well. No. These are completely different. MBUF_FAST_FREE is an optimisation technique, it's in the offload namespace. Whilst "negotiate metadata" does not offload anything. It just tells the PMD to enable *delivery* of some data *when it is present*. And whether it will be present or not, - this is decided by flow actions. And, flow actions, in turn, belong in the domain of decisions made by a specific person operating the application. So no need to remove FAST_FREE. > > >