Re: MirageOS community meeting on Mon Oct 27th 10 - 12 CET

[Hannes Mehnert <hannes@xxxxxxxxxxx>]

Dear everyone,

let's have a next meeting next Monday.


Have a nice day,

Hannes


The minutes from the September meeting are following:

- Participants: Hannes, Pierre, Sai, Virgile, Reynir, Sam, yomimono

## who's around?
### Sai
is a research scholar working with KC Sivaramakrishnan; in systems and 
security. Working on porting MirageOS to RISC-V, and adding 
compartmentalization to it.
### Reynir
is in Denmark -- Sai means tough in Danish; works at robur.coop on 
MirageOS, and applications using MirageOS
### Virgile
works at Tarides with Sam; mainly interested on the Unikraft backend for 
MirageOS (esp. performance related) - to get MirageOS into space
### Pierre
in France, works on MirageOS and QubesOS; so on the Xen backend
### Hannes
works on MirageOS as part of robur.coop; goal is to get MirageOS deployed
### Sam
works at Tarides, on the Unikraft backend. Wonders whether it works for 
other people than himself
## Mirage release, PRs
- hannes will merge and cut a release
- Virgile asked about the workload, and working on issues and review of 
PRs is always welcome
- for unikraft, there are some outstanding PRs

### PR "Adding local libs feature"
- https://github.com/mirage/mirage/pull/1609
- there are some issues with CI

### Unikraft https://github.com/mirage/mirage/pull/1607

### git-kv https://github.com/mirage/mirage/pull/1606

## CI of mirage/mirage
- based on https://github.com/ocurrent/mirage-ci
- there's https://github.com/ocurrent/mirage-ci/pull/51
- our goal would be to have one build with 4.14 and one with 5.3
- Virgile will either ping Mark or review/merge

## Sai: Porting MirageOS to RISC-V

- already ported version 3.10 by:
  - mimicking what solo5 does
  - having specific cross-compiled versions of packages
- how to get started to port it over to 4.x?
- there's the ocaml-solo5 package which needs RISC-V support
- the goal is a bare-metal version

## ocaml-solo5 / ocaml-unikraft and OCaml 5.4?
- Sam: didn't test, but usually there should be only two patches needed
- Sam is happy to PR the 5.4 support for ocaml-solo5/ocaml-unikraft
- Virgile even if we don't have formal time, we should find the time to 
maintain it
## MirageOS on seL4
- there's an intern (Kacper Michalik) at Tarides looking into that

## miou-solo5 work with MirageOS
- uses ocaml-solo5 and miou (https://git.robur.coop/robur/miou-solo5)

## GSO and Xen
- offload packet reassembly/fragmentation to the hardware (or host system)
- Pierre is working hard on that, to gain more performance esp. on Xen
- currently the improvement (on Linux without GSO is 700 MBit, with GSO 
is 3 GBit)
- it's WIP, will give updates at a later time

## bigarray vs bytes
- unrelated to the GSO
- cstruct.t is backed by a Bytes.t instead of Bigarray
- the hope & expectations aren't not yet reflected in the benchmarks
- we need to investigate more to figure out where the performance drops
- helps to reduce (bigarray) allocation by plugging a custom memory 
allocator, and finding the places where bigarrays are still allocated 
(that could be reused)
On 28/08/2025 09:29, Hannes Mehnert wrote:
> Dear everyone,
>
> I hope you had a great summer break. It is my pleasure to invite you to 
> the upcoming MirageOS community meeting on Monday Sep 1st between 10:00 
> and 12:00 CEST.
> We meet as usual at https://meet.jit.si/MirageOS -- the agenda and notes 
> will be discussed and transcribed at https://pad.data.coop/ 
> To6IOSeNSOK9kFVlgo7XWw?both#
>
> Looking forward to see you soon,
>
> Hannes