October 2022 - people - netdevconf.info

0x16, talks: Two new talks
by Jamal Hadi Salim 03 Oct '22

03 Oct '22

In the first talk, Ferenc Fejes, Péter Antal and Márton Kerekes first give an overview of the TSN landscape and then show performance results of the variety of the kernel approaches in relation to scheduling precision when timestamping is done in hardware or software either in the rx or tx direction. Jitter performance results are provided when the datapath is going via the Linux bridge, XDP or AF_XDP. More info: https://netdevconf.info/0x16/session.html?The-TSN-building-blocks-in-Linux In the second talk Justin Iurman and Benoit Donnet introduce Cross-Layer Telemetry (CLT) a mechanism to combine in-band telemetry and Application Performance Management (APM, based on distributed tracing with OpenTelemetry) into a single monitoring tool providing a full network stack observability. The CLT implementation (both for kernel and user spaces) is discussed and evaluated based on a use case. More Info: https://netdevconf.info/0x16/session.html?Cross%E2%80%93Layer-Telemetry-Sup… cheers, jamal

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Early bird registration extended by two days
by Jamal Hadi Salim 02 Oct '22

02 Oct '22

https://netdevconf.info/0x16/registration.html cheers, jamal

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0x16 talk, XPU interaction with the Linux kernel network
by Jamal Hadi Salim 02 Oct '22

02 Oct '22

xPUs[1] have emerged as a way to address host CPU capacity being unable to keep up with link speed growths (1-400 gpbs is here and 1Tbps is coming). Two talks cover xPU interaction with the Linux network stack. Both illustrate offloading of the kernel's VxLAN, L2 forward and routing tables. The first talk, by Sandeep Nagapattinam et al, highlights an abstraction using P4 mapped to OVS. Offloading is done on the Intel Mount Evans IPU[2]. https://netdevconf.info/0x16/session.html?Linux-kernel-networking-accelerat… The second talk, by Alexander Petrovskiy et al, covers a use case of accelerating L3 E-VPN exposing using the kernel tc flower offload mechanism and FRR for BGP distribution. Offloading is done on the Nvidia BlueField DPU[3]. More Details: https://netdevconf.info/0x16/session.html?Towards-a-layer%E2%80%933-data%E2… cheers, jamal [1] XPU is a generalization of what some in the market refer to as a DPU(Data Processing Unit) and others refer to as IPU (Infrastructure Processing Unit). [2]https://www.intel.com/content/www/us/en/products/network-io/infrastructur… [3]https://www.nvidia.com/en-us/networking/products/data-processing-unit/

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ox16 talk, Towards µs Tail Latency and Terabit Ethernet: Disaggregating the Host Network Stack
by Jamal Hadi Salim 01 Oct '22

01 Oct '22

The network stack, from the very first incarnation has offered applications the same "pipe" abstraction; each app writes to a (sender-side) socket "pipe" and the network stack delivers to the receiver side via the NIC queues("pipes") and on the receiver side we have the driver queue(another "pipe") leading to an application "pipe" (socket interface). These pipes are then tied to compute cores which due to their vertical nature cant scale as IO becomes demanding. 100gbps clearly exposes this problem, 400gbps is already being deployed and terabit is on its way. Qizhe Cai et al performed experiments tying cores for network and application processing and assesed applications with long flows and others which are characterized by short flows; in the former the measurements show the bottleneck is the application interfacing compute core (copies etc become dominant) and in the later it is the network processing core (packet/sec is dominant). To resolve these new challenges Qizhe Cai et al introduce NetChannel which hopes to lay the intellectual foundation for a rearchitecture of the kernel network stack. NetChannel disaggregates the tightly-integrated packet processing "pipeline" in today's kernel network stack into layers each of which can be horizontally scaled by throwing more compute or IO/queues on as need basis. More details: https://netdevconf.info/0x16/session.html?Towards-%C2%B5s-Tail-Latency-and-… For netchannel kernel code, see: https://github.com/Terabit-Ethernet/NetChannel cheers, jamal

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