From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) (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 B1F7419BBC for ; Wed, 30 Jul 2025 09:18:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753867138; cv=none; b=Mp1xy1f7lcuDyEIq/yT9zt5B3l1CJXmdNW9+kNt0ZPWACQSMoFGA5rHR2pq+eN70CbsPKslIa3ExXxRQV5CnpINkVIPdk/83KAAk/HDHlvPyn+TnDVmd+TSqOo8KFHtxvyhGgrEh6/vFioDVKkp8fc9J6F2QlHK2Jaxu/HgtoQ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753867138; c=relaxed/simple; bh=qHxnN+p8N/4J+cxhjDNSi04wdr1M2gsZYRjoWDmHqb0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Vog7PHd6Siwrn5/5gae9CxUA3hcoa2XrnarHRbSL0sD/q4Oq1lzpWzEMwb5cppzybbYDoX8LedNJ8TnIa0CEp+DnPpUxMkP0hZMtrOP3I0/3Re1G37Lh0/Ko983LiaeZsT4061C92yhuQ/tKd3FLQYID2u2cKve6KdCHKYD3V2I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=govjFJeD; arc=none smtp.client-ip=91.218.175.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="govjFJeD" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1753867133; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VmYBlQQFDG3sZpmVqr5cFhNHXDXlESp4GGVgtRZrgiI=; b=govjFJeD4BfWbwfYKN2D0S82Fa3yJlgdQYp6pXamckQuhsH1SG0q/pUo5qVm2MQgkZGKUe jflU6UsZUtdNr3rh9wAklaq4Hjl6nk8gX0rlDJT75KOzUTMyTSAHHPYSNpBwmspge2n8D/ fI3ZR/k6ytyBzeGRYcyc/YHpNtfM/+U= Date: Wed, 30 Jul 2025 10:18:46 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [RFC PATCH] ethtool: add FEC bins histogramm report To: Jakub Kicinski Cc: Andrew Lunn , Michael Chan , Pavan Chebbi , Tariq Toukan , Gal Pressman , intel-wired-lan@lists.osuosl.org, Donald Hunter , Paolo Abeni , Simon Horman , netdev@vger.kernel.org References: <20250729102354.771859-1-vadfed@meta.com> <982c780a-1ff1-4d79-9104-c61605c7e802@lunn.ch> <1a7f0aa0-47ae-4936-9e55-576cdf71f4cc@linux.dev> <9c1c8db9-b283-4097-bb3f-db4a295de2a5@lunn.ch> <4270ff14-06cd-4a78-afe7-1aa5f254ebb6@linux.dev> <424e38be-127d-49d8-98bf-1b4a2075d710@linux.dev> <20250729185146.513504e0@kernel.org> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Vadim Fedorenko In-Reply-To: <20250729185146.513504e0@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 30/07/2025 02:51, Jakub Kicinski wrote: > On Tue, 29 Jul 2025 19:07:59 +0100 Vadim Fedorenko wrote: >> On 29/07/2025 18:31, Andrew Lunn wrote: >>>> The only one bin will have negative value is the one to signal the end >>>> of the list of the bins, which is not actually put into netlink message. >>>> It actually better to change spec to have unsigned values, I believe. >>> >>> Can any of these NICs send runt packets? Can any send packets without >>> an ethernet header and FCS? >>> >>> Seems to me, the bin (0,0) is meaningless, so can could be considered >>> the end marker. You then have unsigned everywhere, keeping it KISS. >> >> I had to revisit the 802.3df-2024, and it looks like you are right: >> "FEC_codeword_error_bin_i, where i=1 to 15, are optional 32-bit >> counters. While align_status is true, for each codeword received with >> exactly i correctable 10-bit symbols" >> >> That means bin (0,0) doesn't exist according to standard, so we can use >> it as a marker even though some vendors provide this bin as part of >> histogram. > > IDK, 0,0 means all symbols were completely correct. > It may be useful for calculating bit error rate? The standard doesn't have this bin, its value can be potentially deducted from all packets counter. > > A workaround for having the {-1, -1} sentinel could also be to skip > the first entry: > > if (i && !ranges[i].low && !ranges[i].high) > break; I was thinking of this way, the problem is that in the core we rely on the driver to provide at least 2 bins and we cannot add any compile-time checks because it's all dynamic.