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minutes: IO Visor TSC/Dev Meeting

Brenden Blanco
 

Hi All,

Thank you for joining the call today. Here are my notes from the discussion.

Thanks,
Brenden

=== Discussion ===
Brenden:
* Plan to tag release to coincide with kernel 5.0

Brendan:
* Speaking this weekend at SCaLE in Los Angeles

Yonghong:
* LLVM work
* compile once - run anywhere WIP
* support for static variables

Daniel:
* Global data support work in kernel continues
* Ability to lock maps as read-only
* bugfixes after merge window

Alexei:
* Some thoughts on future work of BPF
* especially with introduction of BTF
* overall needs concerted effort to improve debuggability
* BTF for programs itself with source/type/layout information
* structures for maps and global data
* suggest to always require type information
(already turned on by default in bcc and supported by llvm)
* Some extra hoops to jump through for driver embedded BPF
* to be enabled with a sysctl
* kernel support is ready
* some long tail of support - e.g. systemd has raw assembly BPF
* kconfig option - eventual deprecation
* if kernel is default strict, llvm should automatically emit BTF as well
* memcg accounting patch status?
* Daniel - still being worked on
* proposal to enable the same accounting for verifier memory
* helps to enable verifier multithreading

Jakub:
* question regarding global data atomicity
* Daniel - requires read once / write once instructions to work properly
* some todo work on documentation, interpreter + jit implementations
* depends on architecture (machine word size guarantees only)

Jesper:
* which llvm release supports BTF
* landed in December - will be in 8.0, better in 9.0
* working on tutorial for xdp at netdev
* https://www.netdevconf.org/0x13/session.html?tutorial-XDP-hands-on
* soliciting feedback
* https://github.com/xdp-project/xdp-tutorial/

Saeed:
* request to devote some time in the next meeting to iron out some XDP issues
* please send an agend in reply to the reminder email before next call
* prepare discussion over email in between time

=== Attendees ===
Alexei Starovoitov
Marco Leogrande
Mauricio Vasquez
Paul Chaignon
Brenden Blanco
Jiong Wang
Yonghong Song
Daniel Borkmann
Jesper Brouer
Quentin Monnet
Dan Siemon
Jakub Kicinski
Saeed
John
Yutaro

Saeed Mahameed
 

Hi Guys,

My agenda for next meeting:

1) unifying and centralizing XDP statistics accounting [1].
2) XDP resource management, User API [2].
3) XDP meta data via btf (in kernel BTF registration).
4) all of the above issues share one common problem, which is the lack
of a unified user interface
without it, We really can't make a real progress.

I just sent a proposal [3] for away to achieve the unified interface,
please look it up and let me know your thoughts.
[1] https://github.com/xdp-project/xdp-project/blob/master/xdp-project.org#statistics-per-xdp-action
[2] https://github.com/xdp-project/xdp-project/blob/master/xdp-project.org#better-ndo_xdp_xmit-resource-management
[3] Subject: "[RFC][Proposal] BPF Control MAP"

Thanks,
Saeed

On Wed, Mar 6, 2019 at 12:51 PM Brenden Blanco <bblanco@...> wrote:

Hi All,

Thank you for joining the call today. Here are my notes from the discussion.

Thanks,
Brenden

=== Discussion ===
Brenden:
* Plan to tag release to coincide with kernel 5.0

Brendan:
* Speaking this weekend at SCaLE in Los Angeles

Yonghong:
* LLVM work
* compile once - run anywhere WIP
* support for static variables

Daniel:
* Global data support work in kernel continues
* Ability to lock maps as read-only
* bugfixes after merge window

Alexei:
* Some thoughts on future work of BPF
* especially with introduction of BTF
* overall needs concerted effort to improve debuggability
* BTF for programs itself with source/type/layout information
* structures for maps and global data
* suggest to always require type information
(already turned on by default in bcc and supported by llvm)
* Some extra hoops to jump through for driver embedded BPF
* to be enabled with a sysctl
* kernel support is ready
* some long tail of support - e.g. systemd has raw assembly BPF
* kconfig option - eventual deprecation
* if kernel is default strict, llvm should automatically emit BTF as well
* memcg accounting patch status?
* Daniel - still being worked on
* proposal to enable the same accounting for verifier memory
* helps to enable verifier multithreading

Jakub:
* question regarding global data atomicity
* Daniel - requires read once / write once instructions to work properly
* some todo work on documentation, interpreter + jit implementations
* depends on architecture (machine word size guarantees only)

Jesper:
* which llvm release supports BTF
* landed in December - will be in 8.0, better in 9.0
* working on tutorial for xdp at netdev
* https://www.netdevconf.org/0x13/session.html?tutorial-XDP-hands-on
* soliciting feedback
* https://github.com/xdp-project/xdp-tutorial/

Saeed:
* request to devote some time in the next meeting to iron out some XDP issues
* please send an agend in reply to the reminder email before next call
* prepare discussion over email in between time

=== Attendees ===
Alexei Starovoitov
Marco Leogrande
Mauricio Vasquez
Paul Chaignon
Brenden Blanco
Jiong Wang
Yonghong Song
Daniel Borkmann
Jesper Brouer
Quentin Monnet
Dan Siemon
Jakub Kicinski
Saeed
John
Yutaro