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 5FBB345EC8; Tue, 17 Dec 2024 07:07:22 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 2D7EF40265; Tue, 17 Dec 2024 07:07:22 +0100 (CET) Received: from shelob.oktetlabs.ru (unknown [91.220.146.113]) by mails.dpdk.org (Postfix) with ESMTP id 7E3F640261 for ; Tue, 17 Dec 2024 07:07:21 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 shelob.oktetlabs.ru CE5D45E DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=oktetlabs.ru; s=default; t=1734415639; bh=0iQvpXCC6WaChyEbyQsr0HRfhPGa2FkDYMgPPT8nEUs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=GXo7dJchGFjBhhxq9/c3GrLH6UE+HRktXyIE1Uslofp4sKGuWhAJaTjflpQv7FQ5b VCRsR9ivlZsLunYrm8LNuK9oLaF8xGodBLFja1KSubPjg+VHpUoyAF/FnP6+3C29hq 5R+A4nb/yxSO+SIh05AG3+thl1pK+PNwKfApZCcc= Received: from [192.168.38.17] (aros.oktetlabs.ru [192.168.38.17]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by shelob.oktetlabs.ru (Postfix) with ESMTPSA id CE5D45E; Tue, 17 Dec 2024 09:07:19 +0300 (MSK) Message-ID: Date: Tue, 17 Dec 2024 09:07:19 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/5] ethdev: check that device supports deferred start To: Stephen Hemminger Cc: dev@dpdk.org, Thomas Monjalon , Ferruh Yigit References: <20241213214929.817688-1-stephen@networkplumber.org> <20241214180843.6662-1-stephen@networkplumber.org> <20241214180843.6662-2-stephen@networkplumber.org> <9c5a3e1e-a1b7-4f3f-96f5-674031de6e15@oktetlabs.ru> <20241216105812.28dc5a9b@hermes.local> Content-Language: en-US From: Andrew Rybchenko Organization: OKTET Labs In-Reply-To: <20241216105812.28dc5a9b@hermes.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 12/16/24 21:58, Stephen Hemminger wrote: > On Sun, 15 Dec 2024 11:56:55 +0300 > Andrew Rybchenko wrote: > >> On 12/14/24 21:07, Stephen Hemminger wrote: >>> The check for supporting deferred start should be handled at >>> the ethdev level for all devices. >> >> It is a good idea to check it on ethdev level. >> >> Strictly speaking presence of queue start/stop callback does not mean >> support for deferred start right now. It is possible to use stop/start >> without deferred start feature. > > Right, there are drivers that define the callback but have no logic > in place to do deferred start. They just ignore the flag. > Drivers with this odditiy are: > ark, atlantic, cxgbe, enic, hinic, ipn3ke, nfb, nfp, ntnic > This patch set won't change that. > > There are also some drivers which claim to support queue start/stop > in the documentation, but there is no functions: > virtio, mana, netvsc, mlx4, vmxnet3 > Will fix that in next version of this series. > >> >> However, such check is much better than nothing since deferred start >> definitely requires queue start callback. >> >> It would be good to clarify it in the documentation. >> doc/guides/nics/features.rst does not mention deferred start at all. >> In fact, I don't mind to couple deferred start to queue start/stop >> features. > > It is a bug that the drivers that do queue start/stop and don't > implement deferred start. There is no hardware reason to not support > it, just missing feature during driver development. I agree. Please, don't forget to add rx_deferred_start and tx_deferred_start to queue start/stop features in doc/guides/nics/features.rst. >> >> One nit below. >> >> Anyway: >> Acked-by: Andrew Rybchenko