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
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