Re: upcoming MirageOS meeting 2022-09-21

[Hannes Mehnert <hannes@xxxxxxxxxxx>]

Hello,

below is the notes we took during the meeting. The next one is in three 
weeks (Oct 12th).
Best,

Hannes

# mirage 2022-09-21

participants: christiano, reynir, hannes, thomas leonard, rand, anil, 
dave, mindy
## mirage-kv changes
- released as mirage-kv 5.0
- get_partial, size, set_partial, rename
- at the moment, none mirage-kv implementation supports the new interface
- ocaml-tar has a PR that makes it a Mirage_kv.RW (e.g. used by 
https://git.robur.io/robur/opam-mirror)
- TODO: setup and write a blog entry (for mirage.io) about opam-mirror

## mirage-flow changes
- dave scott approved the shutdown PR 
(https://github.com/mirage/mirage-flow/pull/48)
- read semantics (and buffer ownership, 
https://github.com/mirage/mirage-flow/issues/46)
- reading eio rationale 
(https://github.com/ocaml-multicore/eio/blob/main/doc/rationale.md#indicating-end-of-file), 
the `` Ok `Eof `` signalling is bad for performance -- TODO: benchmark 
this claim
## use eio in mirageos?
- just use eio as a dropin, select a backend
- for performance and getting rid of functors, plus direct style
- lucas worked at it: https://github.com/TheLortex/mirage-monorepo
- the eio core is independent of Unix
- to use eio in MirageOS, solo5 needs some support (christiano will work 
on it)
- instead of Lwt_main, it could run Eio_main (and use Lwt_eio), to 
migrate incrementally
- what is needed for OCaml 5 & MirageOS?
-- a pthread implementation (in ocaml-solo5?)
-- an eio backend, and hooking up the OCaml TCP/IP stack as a net 
implementation
-- domain support (and eventually domain overcommit) [eventually 
preemption?]
-- structured concurrency (for eio, for mirage)

## mirage-block sector alignment
- mirage-block read and write is done aligned on sectors
- on unix, if the image file is not sector-aligned, some 0s are added at 
the end
- on solo5, only full sectors can be read and written (the last bytes 
couldn't be read or written)
- detour: mirage-block-unix has a buffered option
- https://github.com/mirage/mirage-block-unix/pull/117
- https://github.com/Solo5/solo5/pull/527
--> good to merge and release :D

## ocaml-mbr
- also got revived and revised
- ready to release (but is the check "at most one active partition needed")

## tls-eio

- https://github.com/mirleft/ocaml-tls/pull/451
- please review and merge
- there's a kludge to remove tls-async from CI for OCaml 5.0

## move cstruct.t to use bytes (at least for OCaml 5.0)
- faster and slab allocated

## eio webserver+LE? (anil)
- we're pretty close: cohttp, tls
- someone has a eio&let's encrypt stuff?
- mindy is looking it up
- tlstunnel, contruno, unipi, (canopy)

## data center from packet.net is demolished, we need to move mirage.io 
by end of november
## next call: Oct 12th 14:00 CEST