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[204.195.96.226]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-435e132368csm7770463f8f.31.2026.01.28.09.36.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jan 2026 09:36:13 -0800 (PST) Date: Wed, 28 Jan 2026 09:36:09 -0800 From: Stephen Hemminger To: Scott Mitchell Cc: dev@dpdk.org Subject: Re: [PATCH v1 3/3] net/af_packet: software checksum and tx poll control Message-ID: <20260128093609.71674748@phoenix.local> In-Reply-To: References: <20260127181355.98437-1-scott.k.mitch1@gmail.com> <20260127181355.98437-4-scott.k.mitch1@gmail.com> <20260127105749.2e2059a2@phoenix.local> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Tue, 27 Jan 2026 23:05:54 -0800 Scott Mitchell wrote: > > I don't think each driver should be doing its own checksum helper. > > It should be done at application or through libraries. > > All modern hardware does checksum offload, so if it doesn't probably > > a driver bug. > > The goal from the app perspective is to set rte_eth_txmode.offloads > consistently across PMDs. Hardware devices are good but software > devices like af_packet don't provide a consistent experience. The > approach in this patch is similar to existing software eth devices tap > [1] and vhost [2]. In v2 I will share checksum code with tap to avoid > duplication and ensure they remain consistent. > > [1] https://github.com/DPDK/dpdk/blob/v25.11/drivers/net/tap/rte_eth_tap.c#L559-L624 > [2] https://github.com/DPDK/dpdk/blob/v25.11/drivers/net/vhost/rte_eth_vhost.c#L317-L357 > > > Needs to be a separate patch. Don't do two things in one patch. > > Not sure if some variant of the existing configure thresholds > > could be used for this. > > ack, will split txpoll control. I'm not aware of any other way to > prevent poll if dpdk tx is faster than kernel rx. Well tap should NOT be doing software GSO and LRO in DPDK. The kernel driver has ability to do that, and is better done there.