From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Date: Wed, 9 Dec 2020 08:41:05 -0700 Subject: [Intel-wired-lan] [PATCH v2 bpf 1/5] net: ethtool: add xdp properties flag set In-Reply-To: <20201209125223.49096d50@carbon> References: <20201204102901.109709-1-marekx.majtyka@intel.com> <20201204102901.109709-2-marekx.majtyka@intel.com> <878sad933c.fsf@toke.dk> <20201204124618.GA23696@ranger.igk.intel.com> <048bd986-2e05-ee5b-2c03-cd8c473f6636@iogearbox.net> <20201207135433.41172202@carbon> <5fce960682c41_5a96208e4@john-XPS-13-9370.notmuch> <20201207230755.GB27205@ranger.igk.intel.com> <5fd068c75b92d_50ce20814@john-XPS-13-9370.notmuch> <20201209095454.GA36812@ranger.igk.intel.com> <20201209125223.49096d50@carbon> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On 12/9/20 4:52 AM, Jesper Dangaard Brouer wrote: >>> still load and either share queues across multiple cores or restirct >>> down to a subset of CPUs. >> >> And that's the missing piece of logic, I suppose. >> >>> Do you need 192 cores for a 10gbps nic, probably not. >> >> Let's hear from Jesper :p > > LOL - of-cause you don't need 192 cores. With XDP I will claim that > you only need 2 cores (with high GHz) to forward 10gbps wirespeed small > packets. You don't need 192 for 10G on Rx. However, if you are using XDP_REDIRECT from VM tap devices the next device (presumably the host NIC) does need to be able to handle the redirect. My personal experience with this one is mlx5/ConnectX4-LX with a limit of 63 queues and a server with 96 logical cpus. If the vhost thread for the tap device runs on a cpu that does not have an XDP TX Queue, the packet is dropped. This is a really bizarre case to debug as some packets go out fine while others are dropped.