From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B12F320CC6; Mon, 18 Aug 2025 13:56:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755525398; cv=none; b=NBtvxL97a+rD+/WlDS9Fz27p3mAc7vAFXSrN6M0tuQte1kKjTZvydZ/W8TMjHOBahK6IpOi3baMAYcV6a4D9Y4rN2tEUn4lOZnVqa7qcwHUh6b7ta+fpDgc2xjM9cALS6VkqD3ScXSYawaF675LUYQtXM3vKq0KsALKYj69rXzc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755525398; c=relaxed/simple; bh=HrrAxyj61SLnsN3GJ6LjWToWuINFN/Kn5UpaU740itM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Fwb4cEwTPADVyLEqbuOujpbX3r/r59Cjm1PsOXAYRiQcvQ1mMwC82MUVdifRynlGf1aM1pTq7soealwx2pLj/pVGahzPFs91YQPiSWchIzraepc7zAeCuVrnvas63i8slYUqD2gyguN90EmaVBng7z+IHUrW6Kn26x8uH9N8pck= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=D+e//LQC; arc=none smtp.client-ip=209.85.128.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="D+e//LQC" Received: by mail-wm1-f46.google.com with SMTP id 5b1f17b1804b1-45a1b0becf5so21594955e9.2; Mon, 18 Aug 2025 06:56:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1755525394; x=1756130194; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=hBAG0Fay451JgNwYj7hM+/kGoelDE4FVCawIWFGrRP8=; b=D+e//LQC9bRe4e/Z2lZ42tSlY/Hc2aoh7W3PzN9dAqETkL0STzNDQ0lyHTvhvr2TQr on1Yl10h6bClmYxj6D/SOsidDoGrAy4qJsSLQqi9u9wSggpekH1hS3RShtQb88b1y7XX KTCIadI+ZwqLFUUZhwJqwN+90TZl4OWfgSL9O5iTOCKV/wJVVJ9hPwgrKUl414tfhk6h ppHXk04i5oWjdmlkwXl5L7RReI5Jcb8TZy86nKEEkOCCp6XYJBzE0XHT04A3WmeBol5d x7Xn+OJkXumcLeHHXjjQNADGCRyc7McX6P7uylBNEGMTBOXJ+NmIctahH+c122qlmLMq FRvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755525394; x=1756130194; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=hBAG0Fay451JgNwYj7hM+/kGoelDE4FVCawIWFGrRP8=; b=e0N0tcVp/txAwgzeCttdl7COwS4JQg92adtOdUpgNQ1UszuJ8zaE+x+kUzNGL+8INK KLWonhfhWM3h/ZtR5F7te7+7cChk8NnP1qkZuyA5908wKgVC+EWak3xChRuGaMLoedZQ x9NW/ik06jL5F3FcJ7C3rfzjySMIjMJqa3zgXNZ9HjXn3cIaycpTdDMKiDrlWGUMQ3Xv UxF7CN33iDs/jyL0/oir36Wx/bpa0Wlk+IiYIQwNxtS+dbzh7PK4sfv6ZPBOejTWbZmS Km7kohNs4caYcDrxKWrOc1WtArAck3tXIvnlIJGdGgBlifZaJcnS9edB3EwASdzyqeYd kkog== X-Forwarded-Encrypted: i=1; AJvYcCUEzylFtOfpbJ6mOWxfU7+2WSH4ApDsAOVE5OWVoGYow52buwEY67APxt4CrjBPtMb7BKqUCqLpbA==@vger.kernel.org, AJvYcCWlWE4rbzLpArGms9ksdk5tlqPZtA1ikti40/bsgDBFbJrKETvONZIGpOvOuk6QQQmrLqiOw46W+RxTWThg@vger.kernel.org, AJvYcCX7+8FCUaL3tSi2EBl3RYHfxbGRvuOtgj2zcRq4ImS+salWadQ94X3Vi7soXFa+RYmvkecOYwcO@vger.kernel.org X-Gm-Message-State: AOJu0YynkseXQCtV7Y+ZtAYXyHxw/NC/sNBsmuSKbuMqF1ZMOT3A7F/b e2elfYj5rPUQCJhqG3kdzWPa4QlJiWYv6ftHnzTfvuLKYcRLS6JkWvGP X-Gm-Gg: ASbGnct3JRIXjJeVMeOKm2kS6XeytZN58t7kqGbmfkGw/sSrvmiuVvb2R9Y6qIHLsJg 8qecovkamSEvU8YRQCS1BL4IOzvaZzCpO1YYrwaK2GB9lZUy0232ReIfH/XMNHsspwwRgcV6TOd 1zEJh9H5iXfXraGfSDGgHiC7/B1o/NaLbWm4kQtWRlnHmaJapDclWfrGAutDM16XfBXKF3Fuym+ 7ALgwvG+7lVtHejV1a8fTcxK4XZU2cShslXwJCUCzYrIWsjB2q74pkCgEGi+g4DbbOqwMvaICsN dO9Ony+eqMS1WGrtQiqXDbrOUM73mgk+e5RZqf213+kP1SsT+IpphLR+whs8dAIW85HBVu/INvF /NoJqI+CHM4Whd0ZbGdK2DstfItixyKTyXQ== X-Google-Smtp-Source: AGHT+IEX7pzIuAwqyMznwnGBXAQ/IYXLai9r4ecCjkFzntVgaCB8J6e+LGm7kUWPJDcSneo0XZSz+A== X-Received: by 2002:a05:600c:1c11:b0:453:78f:fa9f with SMTP id 5b1f17b1804b1-45a21800120mr95968575e9.11.1755525393444; Mon, 18 Aug 2025 06:56:33 -0700 (PDT) Received: from 127.0.0.1localhost ([185.69.144.43]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45a1b899338sm91187345e9.7.2025.08.18.06.56.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Aug 2025 06:56:32 -0700 (PDT) From: Pavel Begunkov To: Jakub Kicinski , netdev@vger.kernel.org Cc: asml.silence@gmail.com, Eric Dumazet , Willem de Bruijn , Paolo Abeni , andrew+netdev@lunn.ch, horms@kernel.org, davem@davemloft.net, sdf@fomichev.me, almasrymina@google.com, dw@davidwei.uk, michael.chan@broadcom.com, dtatulea@nvidia.com, ap420073@gmail.com, linux-kernel@vger.kernel.org, io-uring@vger.kernel.org Subject: [PATCH net-next v3 02/23] docs: ethtool: document that rx_buf_len must control payload lengths Date: Mon, 18 Aug 2025 14:57:18 +0100 Message-ID: <353e0195a0f44800c0b5aa4a6d751d3655d9842b.1755499376.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jakub Kicinski Document the semantics of the rx_buf_len ethtool ring param. Clarify its meaning in case of HDS, where driver may have two separate buffer pools. The various zero-copy TCP Rx schemes we have suffer from memory management overhead. Specifically applications aren't too impressed with the number of 4kB buffers they have to juggle. Zero-copy TCP makes most sense with larger memory transfers so using 16kB or 32kB buffers (with the help of HW-GRO) feels more natural. Signed-off-by: Jakub Kicinski Signed-off-by: Pavel Begunkov --- Documentation/networking/ethtool-netlink.rst | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst index ab20c644af24..cae372f719d1 100644 --- a/Documentation/networking/ethtool-netlink.rst +++ b/Documentation/networking/ethtool-netlink.rst @@ -966,7 +966,6 @@ Kernel checks that requested ring sizes do not exceed limits reported by driver. Driver may impose additional constraints and may not support all attributes. - ``ETHTOOL_A_RINGS_CQE_SIZE`` specifies the completion queue event size. Completion queue events (CQE) are the events posted by NIC to indicate the completion status of a packet when the packet is sent (like send success or @@ -980,6 +979,11 @@ completion queue size can be adjusted in the driver if CQE size is modified. header / data split feature. If a received packet size is larger than this threshold value, header and data will be split. +``ETHTOOL_A_RINGS_RX_BUF_LEN`` controls the size of the buffers driver +uses to receive packets. If the device uses different buffer pools for +headers and payload (due to HDS, HW-GRO etc.) this setting must +control the size of the payload buffers. + CHANNELS_GET ============ -- 2.49.0