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 2A6CF41BA0; Wed, 1 Feb 2023 16:23:09 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 0410F42B8E; Wed, 1 Feb 2023 16:23:09 +0100 (CET) Received: from mail-vs1-f41.google.com (mail-vs1-f41.google.com [209.85.217.41]) by mails.dpdk.org (Postfix) with ESMTP id DBB834021D for ; Wed, 1 Feb 2023 16:23:07 +0100 (CET) Received: by mail-vs1-f41.google.com with SMTP id s24so12646350vsi.12 for ; Wed, 01 Feb 2023 07:23:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=3zuv8awZUoZ0cWzUufw+aqBSK/lzDP35ZNg7k67zD7s=; b=WQKBKCdoPwStBAhB4GZYUYlSXtLhJYTc7o/IcbGxcfk+MdU/IHoxthvOgr0qja+Et7 sUrSwOKerAwunUjXIJKffjWkzcD21D/4AT7JcUTreq7bb24V05GydtjM6HCPL/huG5C4 +kcFI4ysbjgFWweYY8OE6SyhGW8E8hGNNHdVBwi/n3xbLHDA/jGFnxxqbl7bojnZjmGf zQ9v3E4C6hgZ5kD5tsWsEGoWxQ7FpsWXEy0o/rrnoIEQaeAc3F+RQiYaVcbCtDGHC3zZ qJyOU1DdnbUDnOoarcig2C4hB2PEuiytkoYm1yYhEvF2/PT3VZzMYVdwiwpCybyya8P9 yytQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=3zuv8awZUoZ0cWzUufw+aqBSK/lzDP35ZNg7k67zD7s=; b=gzvhW7z7esqrw3df+7/l4Tglp71LabGFZcb5tVPAfUDjC/cx/WR1UJJS1kjqns8u1R Spk7CisjmidIVDo8nOx0EGr2BFF1stSq7MMMmyPLKs7qNeNag/8aDsoVUnmGOCAZNnQr aS+UnOhfcp6WbNqz+pPa5IMGNHCSEPevhW9iVinNzoyH4/lsK9lCX4elEtBWgMkacvgs 9YXABFisa7e50MjGXvnIqgxMGx98jM2sw5umrfd8PfsIzLhDWA70BxoKJDzcrIoVIY5j LM6BZuNeG2kI1DoAgMRoWbcXnnxE8YtyajJ1tgr3seajT+uT6gOPy8eIiqJ/iREKjy+O 6I5A== X-Gm-Message-State: AO0yUKXeyaM6HCSzKEFdEiUhO90MovyrfF6+k0XK4tUrmxC9VtonXauS TsW1Q3xF0qbWm/Ts2a7GH+BVHE/9TnblV57hHOQ= X-Google-Smtp-Source: AK7set8ImLUAYfBv4pL051D3YknLB0zxMHC3AmbmKFl3Y5UT9VvOKj9AXy28032JYeOXRdXseXMG04dfugbCfWEsQqo= X-Received: by 2002:a67:fb81:0:b0:3f1:b35:72d2 with SMTP id n1-20020a67fb81000000b003f10b3572d2mr459129vsr.73.1675264987199; Wed, 01 Feb 2023 07:23:07 -0800 (PST) MIME-Version: 1.0 References: <20221220200250.2413443-1-hpothula@marvell.com> <98a80c20-a5e4-deea-f7dc-c6aa5d52800b@oktetlabs.ru> <2490780.4XsnlVU6TS@thomas> <22a65100-bee8-1726-6e27-14b9028a29d4@amd.com> <01d3b455-3f3e-2658-db51-4da7cfc3cdeb@amd.com> In-Reply-To: <01d3b455-3f3e-2658-db51-4da7cfc3cdeb@amd.com> From: Jerin Jacob Date: Wed, 1 Feb 2023 20:52:40 +0530 Message-ID: Subject: Re: [EXT] Re: [PATCH v5 2/2] app/testpmd: add command to process Rx metadata negotiation To: Ferruh Yigit Cc: Thomas Monjalon , Andrew Rybchenko , Ori Kam , Ivan Malov , Nithin Kumar Dabilpuram , Aman Singh , Yuying Zhang , "dev@dpdk.org" , Hanumanth Reddy Pothula , Slava Ovsiienko , Jerin Jacob Kollanukkaran , "david.marchand@redhat.com" Content-Type: text/plain; charset="UTF-8" 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 On Wed, Feb 1, 2023 at 8:20 PM Ferruh Yigit wrote: > > On 2/1/2023 1:48 PM, Jerin Jacob wrote: > > On Wed, Feb 1, 2023 at 5:06 PM Ferruh Yigit wrote: > >> > >> On 2/1/2023 11:15 AM, Jerin Jacob wrote: > >>> On Wed, Feb 1, 2023 at 4:35 PM 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. > >>> > >>> IMO, We tune the system resources like queue depth not the disabling > >>> features for raw performance. > >>> queue depth etc people know to tune so it is obvious. What is not > >>> obvious is, testpmd only > >>> negotiated some features by default.I am not using that feature, hence > >>> I need to explicitly > >>> disable it. > >>> > >> > >> When 'rte_eth_rx_metadata_negotiate()' API is NOT used at all, and I > >> believe that is the case for almost all applications since API is a > >> relatively new one, PMD default behavior should be to enable Rx metadata > >> flow rules, in case user requests them later. > >> > >> So, enabling all in application is same with not calling the API at all. > >> > >> In this perspective, disabling Rx metadata is additional > >> optimization/tuning that application can do if it is sure that Rx > >> metadata flow rules won't be used at all. > >> And API is more meaningful when it is used to disable Rx metadata. > >> > >> I think it is reasonable to enable all Rx metadata by default in testpmd > >> with a capability to disable it when wanted. > >> > >> OR > >> > >> May be we don't call 'rte_eth_rx_metadata_negotiate()' API by default in > >> testpmd, it is only called when it is requested explicitly from user, > >> enable or disable. > > > > Second option looks good to me. > > When > > 1) user request for action which is needed negotiate(), > > AND > > 2) rte_eth_rx_metadata_negotiate() != ENOSUP > > then, testpmd print a warning that need to enable > > rte_eth_rx_metadata_negotiate(). > > > > We are not suggesting same thing. > > What you described above assumes PMD disabled Rx metadata flow rule > support by default, and it needs to be enabled explicitly by > 'rte_eth_rx_metadata_negotiate()' API. This API becomes mandatory for > functionality. > > As far as I understand PMD wants to disable this flow rule by default > because of performance concerns. But this creates inconsistency between > PMDs, because rest of them will enable this flow rule by default (if it > is supported) and be ready to use it when proper flow rule created. > > With this approach some PMDs will need 'rte_eth_rx_metadata_negotiate()' > to enable Rx metadata flow rules, some won't. This can be confusing for > applications that *some* PMDs require double enabling with specific API > call. > > > Instead what I was trying to suggest is reverse, > all PMDs enable the Rx metadata flow rule by default, and don't require > double enabling. > But if application knows that it won't use Rx metadata flow rule, it can > disable it to optimize the performance. > This makes 'rte_eth_rx_metadata_negotiate()' functionally optional, and > for testpmd context it can be called via a command on demand by user for > optimization purpose. This won't solve concern I have outlined earlier[1]. I think, The part of the problem there is no enough adaption of rte_eth_rx_metadata_negotiate(), The view is total different from PMD maintainer PoV vs testpmd application PoV. Just to avoid back and forth. We will call off this patch and remove rte_eth_rx_metadata_negotiate() PMD callback from cnxk driver. Keep it as old behavior, so we don't need to care about rte_eth_rx_metadata_negotiate(). [1] 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". 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. > > > > > > > >>> > >>>> > >>>>>> 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. > >>> > >>> if you see MBUF_FAST_FREE, it does nothing. Actually, > >>> !MBUF_FAST_FREE is doing more work. > >>> > >>> > >>>> > >>>> > >> >