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 4B2D5C43334 for ; Tue, 21 Jun 2022 19:52:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245048AbiFUTwv (ORCPT ); Tue, 21 Jun 2022 15:52:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231739AbiFUTwu (ORCPT ); Tue, 21 Jun 2022 15:52:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A8962DAA2 for ; Tue, 21 Jun 2022 12:52:50 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B9BF06179F for ; Tue, 21 Jun 2022 19:52:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC833C3411C; Tue, 21 Jun 2022 19:52:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655841169; bh=FMlapEJiq1g56gXJR+WVCOKa/JCBjNblRyCYan0URYU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fRxGRXxAAujre7e0h4Nhbbt4i7mtoMDPPEQTHAreng1kC3mfayPJCiPkuVSr+UcAt YySWsCmK4/axknInpw6N73gt22KgMC04+7EJzr9e1Ak/uHIqklldckR9RWsuSl8V82 CIq150PnRKj7NPdQDhODSAYWhobqCCq1UYZJJYLH33eO1CGdER52FiXpJqaZ7VOKKn 5eswWRwV2HY9eT0ixwrTq6UvkNqlA5cbegWBauR87EYGGVEp6xJtFXojxUGzk36jB5 en56uUy2zPQTUvzobxfZwDpDgEDx1E+u3IsF1vMVW0DDWykDOFec7Mt2RqvsIE35qM /LJVBKUaqHHVg== Date: Tue, 21 Jun 2022 12:52:39 -0700 From: Jakub Kicinski To: Jay Vosburgh Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , netdev@vger.kernel.org, Jonathan Toppins , Veaceslav Falico , Andy Gospodarek Subject: Re: [PATCH net] veth: Add updating of trans_start Message-ID: <20220621125233.1d36737b@kicinski-fedora-PC1C0HJN> In-Reply-To: <20220617175550.6a3602ab@kernel.org> References: <9088.1655407590@famine> <20220617084535.6d687ed0@kernel.org> <5765.1655484175@famine> <20220617124413.6848c826@kernel.org> <28607.1655512063@famine> <20220617175550.6a3602ab@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 17 Jun 2022 17:55:50 -0700 Jakub Kicinski wrote: > > >I presume it needs it to check if the device has transmitted anything > > >in the last unit of time, can we look at the device stats for LLTX for > > >example? > > > > Yes, that's the use case. > > > > Hmm. Polling the device stats would likely work for software > > devices, although the unit of time varies (some checks are fixed at one > > unit, but others can be N units depending on the missed_max option > > setting). > > > > Polling hardware devices might not work; as I recall, some > > devices only update the statistics on timespans on the order of seconds, > > e.g., bnx2 and tg3 appear to update once per second. But those do > > update trans_start. > > Right, unfortunately. > > > The question then becomes how to distinguish a software LLTX > > device from a hardware LLTX device. > > If my way of thinking about trans_start is correct then we can test > for presence of ndo_tx_timeout. Anything that has the tx_timeout NDO > must be maintaining trans_start. So what's your thinking Jay? Keep this as an immediate small fix for net but work on using a different approach in net-next?