minutes: IO Visor TSC/Dev Meeting

Brenden Blanco

Hi All,

Thanks for the good discussion today! Below are my notes.


=== Discussion ===

* https://github.com/savisko/katran/tree/xdp_off
* Mellanox presentation on XDP + Katran
* offload tc XDP programs to hardware nic
* Example application: Katran from Facebook
* Control is implemented as a C++ library (example is open source)
* Katran DP already implemented in XDP
* Parsing + extract flow ID
* lookup key generation
* counter update
* packet modified to forward to other IP
* Accelerate marking of flows in hardware
* XDP metadata to pass mark field from hardware to xdp program
* struct xdp_md_mark {
__u32 mark)
* if (mark_ptr + 1 <= data)
markID = mark_ptr->mark;
* per-CPU XDP map to convert mark -> real flow information
mark == 0 implies new flow
* original XDP slow-path has get_packet_dst() to create LRU mapping
* modified version uses perf event output to notify acceleration helper to
install flow mark in hardware
* perf results:
100 flows: 40+% performance improvements
10k flows: 0-50% performance improvements depending on #rx queues used
Software: 25Mpps
Hardware: 37-39Mpps
* considering changing implementation to mark real server instead of flow
id, to reduce number of entries kept in L1 cache

* Compile once run anywhere work continues
* bitfield handling bugs in IR/debuginfo

* Global support work continues
* BTF side patches submitted to bpf mailing list
* tests included

* 32 bit patch set
* test methodology improvements
* updated patches later in the week
* some concerns around shifts, to be addressed in later improvements

* BTF and compile-once work integration
to share prototype tool with Saeed

* Is there a tool to measure queue latency in qdisc->netdev layer?
* debian/ubuntu are packaging bpftrace
* except libbcc renamed to libbpf_cc
* some issues with mixing iovisor's libbcc and debian's

* Fedora adding packaging support for libbpf

* systemd also adding support for libbpf - link to be provided?

=== Attendees ===
Brenden Blanco
Andril Nakryiko
Daniel Borkmann
Jesper Brouer
Jiong Wang
Marco Leogrande
Michael Savisko
Paul Chaignon
Quentin Monnet
Alexei Starovoitov
Jonathan Lemon
Brendan Gregg
Dan Siemon
Joe Stringer

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