From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E12D0C6FD1D for ; Fri, 31 Mar 2023 03:32:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229830AbjCaDcb (ORCPT ); Thu, 30 Mar 2023 23:32:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229921AbjCaDcV (ORCPT ); Thu, 30 Mar 2023 23:32:21 -0400 Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89113191E5 for ; Thu, 30 Mar 2023 20:32:11 -0700 (PDT) Received: by mail-pg1-x535.google.com with SMTP id q206so12626876pgq.9 for ; Thu, 30 Mar 2023 20:32:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1680233530; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=EpwfiK6OSweJoJ4X70Gvq2mGWAZMiFEn21CRBylaXic=; b=EhMwN94kOyyoVi/0Sl386QIHmZOOCqtHJLNnWCcaaiCu2kGVNimw2OEXYb4KjzKWof FdGkFw47QzD2XMQ4FC4b6x1bl9IlQkGnKx/d2QUh2IfznmfU/LNuLlCoSF1FtVqzOCHs +UEk12JfgJDhLoiQsXrxRIC8lvovl9pcaGohPh3KVpS9IjZ0RAt4Fvao9scyazasjRvd wMgKcrF2NVXsGWyQWtoPmM3CZ46/HskzViomJntBZRf9L2ACcR4MGSntH266Pa6/MJmk d1MR2k5QsDCajr4js8lHXc0GZHadn9ZBTzZZDADVG8QtES2r3f+dYGVBX5QnCQKiXZxH ZKpA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680233530; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=EpwfiK6OSweJoJ4X70Gvq2mGWAZMiFEn21CRBylaXic=; b=5xGRWnuQ6Jad+4l3WYQOXFgSfOC0oRqNHL5KZ4W959h05K9Wle0i8BET37BbHBdapw K8MsWqhJFbvDVL0AeGZJY64Z6GvkueacNW03EpfJcjwPyzw7iHAzNtbP3GZUYgmVeI4C ZWuZYOlyKJtKGbsDVhgw9o3iwkrj5RBVbpKGysNCceRUrYa3HVBa/rKwhdJJ4jXStA0W GcnitxPsM7YDdh6R0W4hO9QddGixbuLBj3mrQ/o4YAurl5Zk2ugQ7ZgjEPB11EaAgQRh 3E8oqXV0JuTCaOA2Z1GPTodcgA9jYqDmT76+1wB8X53ZCsLf1XmZ33x1Qt8I0L2TmNJP jU1Q== X-Gm-Message-State: AAQBX9cRdmR9xghxckv9AGXwDs2xdkctt8eWqRY5LGN6qZkUIm6E1FfY 6hlnYI3f6TYJaK5AqSd2Zp8= X-Google-Smtp-Source: AKy350b6PD6DnstcM9Mow/5ZEgboNm1vDOUst2LezQrwGSsSQ0vLerKoVxiblxtdkSAFrIJiYYJBBQ== X-Received: by 2002:a62:1811:0:b0:62a:4503:53ba with SMTP id 17-20020a621811000000b0062a450353bamr23351014pfy.26.1680233530377; Thu, 30 Mar 2023 20:32:10 -0700 (PDT) Received: from Laptop-X1 ([2409:8a02:7821:7c20:eae8:14e5:92b6:47cb]) by smtp.gmail.com with ESMTPSA id j11-20020aa7800b000000b005895f9657ebsm588838pfi.70.2023.03.30.20.32.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Mar 2023 20:32:09 -0700 (PDT) Date: Fri, 31 Mar 2023 11:32:03 +0800 From: Hangbin Liu To: Jay Vosburgh Cc: Miroslav Lichvar , netdev@vger.kernel.org, "David S . Miller" , Jakub Kicinski , Jonathan Toppins , Paolo Abeni , Eric Dumazet , Richard Cochran Subject: Re: [PATCH net-next] bonding: add software timestamping support Message-ID: References: <20230329031337.3444547-1-liuhangbin@gmail.com> <7144.1680149564@famine> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7144.1680149564@famine> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Mar 29, 2023 at 09:12:44PM -0700, Jay Vosburgh wrote: > >> Would it make sense to check if all devices in the bond support > >> SOF_TIMESTAMPING_TX_SOFTWARE before returning it for the bond? > >> Applications might expect that a SW TX timestamp will be always > >> provided if the capability is reported. > > > >In my understanding this is a software feature, no need for hardware support. > >In __sock_tx_timestamp() it will set skb tx_flags when we have > >SOF_TIMESTAMPING_TX_SOFTWARE flag. Do I understand wrong? > > Right, but the network device driver is required to call > skb_tx_timestamp() in order to record the actual timestamp for the > software timestamping case. > > Do all drivers that may be members of a bond return > SOF_TIMESTAMPING_TX_SOFTWARE to .get_ts_info and properly call > skb_tx_timestamp()? I.e., is this something that needs to be checked, > or is it safe to assume it's always true? > > If I'm reading things correctly, the answer is no, as one > exception appears to be IPOIB, which doesn't define .get_ts_info that I > CAN Find, and does not call skb_tx_timestamp() in ipoib_start_xmit(). Oh.. I thought it's a software timestamp and all driver's should support it. I didn't expect that Infiniband doesn't support it. Based on this, it seems we can't even assume that all Ethernet drivers will support it, since a private driver may also not call skb_tx_timestamp() during transmit. Even if we check the slaves during ioctl call, we can't expect a later-joined slave to have SW TX timestamp support. It seems that we'll have to drop this feature." Thanks Hangbin