Offer to host RISC-V CI runner

[danog]

Description

I have a VisionFive2 board that I currently use to build riscv64 packages for my software and php itself (https://hub.docker.com/r/danog/php), I'd be more than willing to set up a woodpecker runner and submit a PR with the configuration needed to run the php-src testsuite on native riscv64 hardware :)

[mvorisek]

Wouldn't QEMU for RISC testing be better using standard GH (or any Docker based CI)?

[danog]

QEMU is super slow compared to real hardware, for example here are some basic benchmarks compiling php-src, running on my visionfive2 board and on QEMU on an AMD EPYC 7401P:

./configure --enable-debug --without-pcre-jit --without-sqlite3 --without-pdo-sqlite

starfive (1m14s)

real  1m14.050s
user  0m56.293s
sys  0m18.814s

QEMU (6m45s)

real	6m 45.44s
user	5m 52.75s
sys	0m 49.56s

make -j4

starfive (7m52s)

real	7m52.868s
user	27m15.208s
sys	2m27.981s

QEMU: still in progress after 30m, aborted...

AFAIK, all CIs currently used to test other php-src on arm64 and s390x run on native hardware.
Woodpecker is a great FOSS CI system based on Docker meant for self-hosting, unlike GHA self-hosted runners which are an absolute mess to work with (and currently don't support riscv64, unless we were to use a reverse-engineered Golang implementation of GHA runners like https://github.com/ChristopherHX/github-act-runner).

[NattyNarwhal]

I’d be worried about things like QEMU not properly emulating atomics, memory model, etc. Things that aren’t obvious, but can trip you up badly.