From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 03C0D42DE9 for ; Thu, 6 Jul 2023 16:37:41 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 616B0410FA; Thu, 6 Jul 2023 16:37:41 +0200 (CEST) Received: from mail-oo1-f45.google.com (mail-oo1-f45.google.com [209.85.161.45]) by mails.dpdk.org (Postfix) with ESMTP id E520E40A79 for ; Thu, 6 Jul 2023 16:37:40 +0200 (CEST) Received: by mail-oo1-f45.google.com with SMTP id 006d021491bc7-563531a3ad2so503259eaf.3 for ; Thu, 06 Jul 2023 07:37:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20221208.gappssmtp.com; s=20221208; t=1688654260; x=1691246260; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=s8J19PjrykWKWALx0x22N/hCb0UqOlEJ6v3GxUNf5yw=; b=CMxmPORT116KUcFmY+Ytb3f7WHO3nm+FgC4pghpAqMdS5kj+O4YGW6Qaw/vLdvzQ4h XvWdjw1QjYda6Tqk8YQ5+7WYywPPMb8B92tNW86dnDI5VzNlZOILUMaKEb7iGRceYVMv vS4IN1KF82lnxsulkAhlwRmLAbS1QjtanCdlxm85iW/kdju24lvd/PGvL6ytSMHHQmyk T2iYqKuZnsrxNlLQSc/UgE2YLiHhAjKIx6fO4FM6Hiab6XD8fDFznNGMelbR7H+69x+P ifyT/g6hmwPwld+NSpsNUCWXR28WD7eIVeQVmRS4uozEXLYpTG+9hStp52GYn+XfWxHR TTHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688654260; x=1691246260; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=s8J19PjrykWKWALx0x22N/hCb0UqOlEJ6v3GxUNf5yw=; b=ID3y1kGaCrikCj5TrhQ1NXgY068GPYBNalc2MNV7dJQgNEY1fJBE7hUCkMOkgZbaBM rPzWZrLhhfQGmGb8rKJhjeepRMijjG+nEl6vWrXwXgYm0p9wBcMMwEhEDNOta1BAVO14 AN9I42T8eaxj5LcdcBVgabQ8BTl6fz1mbpyc0OWwCd1HScuQKaWHCxB0jm8w+Qg88i54 lxWYxoxpg5XuOrtgz9E/pgdcPYcvUpfy9ARPgK2j/7TRTRc2WD6fWaSSWW3wxiMXMHpo uysETrZ9H+h1XCziw+CdklbMHHshmz1Dowbncljp4CMrYLdsl77G92k9iJtgYElsd5dh XX+A== X-Gm-Message-State: ABy/qLbP9X0RPkdAXMNZRuyfHt7pQGVKc6+lMAmxRXF08Qpq1F98N0LF wnDamEhYZspbjX/XSt9LYCXrdA== X-Google-Smtp-Source: APBJJlEfbsz1uFhxGSQaK8iBl0NNADKkC9hZELExMa3nYOl4zSRpBoD9X6/9BdJpqnsNyMVaFLetIw== X-Received: by 2002:a05:6358:4303:b0:135:3f5c:9675 with SMTP id r3-20020a056358430300b001353f5c9675mr2461732rwc.19.1688654260000; Thu, 06 Jul 2023 07:37:40 -0700 (PDT) Received: from hermes.local (204-195-120-218.wavecable.com. [204.195.120.218]) by smtp.gmail.com with ESMTPSA id e18-20020a637452000000b0055bbc746272sm1406294pgn.17.2023.07.06.07.37.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Jul 2023 07:37:39 -0700 (PDT) Date: Thu, 6 Jul 2023 07:37:37 -0700 From: Stephen Hemminger To: "jiangheng (G)" Cc: "maxime.coquelin@redhat.com" , "chenbo.xia@intel.com" , "users@dpdk.org" Subject: Re: why does virtio not support IPv4 CKSUM? Message-ID: <20230706073737.24bc2201@hermes.local> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org On Thu, 6 Jul 2023 03:47:26 +0000 "jiangheng (G)" wrote: > Hi > > why does virtio not support IPv4 CKSUM? But support TCP/UDP cksum. Because virtio is a software driver developed on Linux and Linux doesn't need/want IP checksum offload. It takes longer to look at offload bits then to compute checksum in SW. > > If not support ipv4 cksum, when I use GRO, the ip cksum of the packets transmitted to ip layer will be incorrect. > I have to calculate ip cksum before packet was transmiited to ip layer. > So why does virtio not support ipv4 cksum ?