Re: minutes: IO Visor TSC/Dev Meeting

Brenden Blanco

On Tue, Apr 2, 2019 at 10:48 AM Saeed Mahameed
<saeedm@...> wrote:

Hi Brenden,

I am sending this on behalf of Michael Savisko, he is having some
difficulties sending emails to the iovisor list.
Sending to the iovisor-dev mailer is gated by a signup requirement, in
order to reduce spam. The signup process should be pretty painless, I
believe it just requires going through an email validation step:

Michael is working on real world use cases for XDP acceleration.
He would like to present and discuss his work and analysis on
accelerating Katran load balancer [1] via meta data offloads.
He will need 10 minutes and will share some slides, i hope we can push
this to tomorrow's meeting agenda.
Sounds good!

Katran modified code is on Github:


On Wed, Mar 20, 2019 at 3:32 PM Brenden Blanco <bblanco@...> wrote:

Hi all,

Thanks for joining the discussion today. Here are the notes; however, this was
a longer discussion and I'm sure I missed some things.


=== Discussion ===

* Some internal BTF work
* Compiler support for static variables
* Some compile-once-run-everywhere work
* Looking for help with issues regarding libbpf packaging/dependencies
* Issue to continue offline, not concluded on the call
* Issue related to function->function call in bcc and compiler optimizations
* Jiong offers to debug the codegen using 32 bit mode

* XDP driver statistics standardization
* All drivers run same entry point for xdp progs
* Why not account stats here?
* Even though xdp program can implement its own statistics
* Many drivers are already paying stats accounting cost
* Just remove unused stats from driver?
* Stats may be used in debugging, but FB for instance is guarding with
static key, wouldn't want extra stats on by default
* Allocating resources for tx queue/redirect?
* Is there a better way to allocate resources when it isn't known that a
program will need queues
* One approach is to attach dummy bpf program
* Resource allocation point when configuring devmap?
* Seems like a clean enough solution, doesn't solve all cases but moves the
ball forward
* BTF metadata structure registration
* Should be queryable from userspace, don't yet have an API for that
* Netlink vs syscall?
* No silver bullet for all use cases
* Hesitation for creating a new object to describe existing objects (bpf
progs, maps)
* BTF is metadata conceptually different from maps, progs
* ethtool? unlikely due to lack of code ownership
* For buffers, something like devlink is more appropriate
* For BTF, bpf() syscall works
* BTF for statistics description (ethtool replacement?)

* verification of static data is working, patches coming soon

=== Attendees ===
Brenden Blanco
Michael Savisko
Alexei Starovoitov
Daniel Borkmann
Jakub Kicinski
Neerav Parikh
Paul Chaignon
Marco Leogrande
Jiong Wang
Andrii Nakryiko
Yonghong Song
William Tu
Joe Stringer
Maciej Fijalkowski
Martin Lau
Mauricio Vasquez
Piotr Raczynski
Quillian Rutherford

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