From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4983138F94 for ; Fri, 1 Mar 2024 01:49:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709257756; cv=none; b=HfWxhN/rIdCtf2rW3/I5pqHT2DNemkYc1Ab5fUEANyAImxUFC8EYghjRQ8Lo+X+J8l8qUCrFUbYWrDdWCxfy7iSpBWkZEDrW+XBZRBWP8qD/pwPhsEew8imvweF3c5lQpH3WX5r7OzUmmjzTKfUCSY7qJEBCbeMJtGpGnOGUOQc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709257756; c=relaxed/simple; bh=x6r2Y5DsuDRLe9aKxr3x8TPe4j53T/4JjcInqksnwpo=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dUMtyR9hqR3unPHLaUdxDjE+HmMUaMJOjRcgvZ1Rbwgobx4ISXBLaAgxY7LHmNOh3FYJQC80BUYkfa3HFMK2YfznM7/001f+oKBmmuQ832/l6RRujJmm6uYpAQfd0TJJaqgdq+Wzc9A/HBpHvWGfxE0C+Eep1cBoKuamU1GVoGY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X+dwGVk6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="X+dwGVk6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BEE6C433F1; Fri, 1 Mar 2024 01:49:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709257755; bh=x6r2Y5DsuDRLe9aKxr3x8TPe4j53T/4JjcInqksnwpo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=X+dwGVk6c/wH4eU1bTuhhv4a0XENi+oFSmpC+2NSqpPS4235ZgxEQnfryeJpcsWT0 iPN/aMLZsR3XX0Gz6weesCnMTOJuKYyouSV0kV2XCYY49jGDEK1sLxmSEsaHLIV1pn 8LyI0KhU/GFUVj7MNw8lohb6hY3XuBjJUBTub9QZH+qtYagELaGTXYFVxZs3889w/j SyaHQgDSbyAq59SHT/VtMaGT8dxfyubTFI3ugqIQeKvKbQfwZsKh/lArxIVf4lBGKe 31zuMHmAB7zTYBz1Z5ZkV53woiEYn/0NSvvCASN5C6lsxFiFFee5rAI3PoFEvvOkWp Ho9Hz4n3rklGA== Date: Thu, 29 Feb 2024 17:49:14 -0800 From: Jakub Kicinski To: Vadim Fedorenko Cc: Jiri Pirko , Michael Chan , davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, pavan.chebbi@broadcom.com, andrew.gospodarek@broadcom.com, richardcochran@gmail.com Subject: Re: [PATCH net-next 1/2] bnxt_en: Introduce devlink runtime driver param to set ptp tx timeout Message-ID: <20240229174914.3a9cb61e@kernel.org> In-Reply-To: References: <20240229070202.107488-1-michael.chan@broadcom.com> <20240229070202.107488-2-michael.chan@broadcom.com> <20240229093054.0bd96a27@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 29 Feb 2024 21:22:19 +0000 Vadim Fedorenko wrote: > > Perhaps, but also I think it's fairly impractical. Specialized users may > > be able to tune this, but in DC environment PTP is handled at the host > > That's correct, only 1 app is actually doing syncronization > > > level, and the applications come and go. So all the poor admin can do > > Container/VM level applications don't care about PTP packets timestamps. > They only care about the time being synchronized. What I was saying is that in the PTP daemon you don't know whether the app running is likely to cause delays or not, and how long. > > is set this to the max value. While in the driver you can actually try > > Pure admin will tune it according to the host level app configuration > which may differ because of environment. Concrete example? > > to be a bit more intelligent. Expecting the user to tune this strikes me > > as trying to take the easy way out.. > > There is no actual way for application to signal down to driver that it > gave up waiting for TX timestamp, what other kind of smartness can we > expect here? Let's figure out why the timeouts happen, before we create uAPIs. If it's because there's buffer bloat or a pause storm, the next TS request that gets queued will get stuck in the same exact way.