Hi all, Thanks for joining the call today. Below is the summary of the topics discussed.
If you are in the Bay Area tomorrow, PLUMgrid will be hosting a meetup to discuss XDP, feel free to join if you can. http://www.meetup.com/Silicon-Valley-Linux-Technology/events/232786938/ =========== On the kernel side, two patches landed recently, both should be available in Linux 4.8: >From myself, the initial xdp framework was accepted into net-next. http://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=22b3548861fb21ad79e0d3afeee123b0eb3912cc >From Sargun Dhillon, experimental support for writing into process memory from a kprobe. http://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=eefc06bd0272264f38f84b10879d3bdb5b5d1ee3 Brendan has been working on some excellent documentation, adding: - An end user guide - A developer tutorial - A developer reference guide Alban had 2 questions/use cases that he shared: 1. Monitor all local connections on a machine Current approach does effectively: - get a list of sockets - usually look in /proc/$PID/... - racy - not for short-lived connections - poll-heavy Instead would like to: - trace connect()/accept()/send()... - kprobe can fill the gap for now - still need tracepoints for tcp+sockets, reliable api - would be nice to have multiple bpf programs per kprobe - this has been brought up before, possible to use tail calls to implement this in bcc without new kernel features 2. Monitor all services in a cgroup, e.g. network bytes sent/recd - Kprobes are global, but often have access to cgroup pathname - Possible to filter/bucket kprobe statistics based on this, but relies on kernel data structures...fragile - Suggest to formalize use case to iovisor-dev list, possible new bpf program type/helper to be discussed there Brendan mentioned a new observability feature they would like: Dynamic USDT probe - node.js/java/language-foo can dynamically generate its own usdt symbol, and add a separate elf section on the fly - still working out what bcc instrumentation this needs, more in the future =========== Attendees: Kyle Laracey Brenden Blanco Deepa Kalani Keith Burns Jesper Brouer Alban Crequy Martin Lau Brendan Gregg
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