mediasoup-worker linux prebuilt with io-uring support (part 1)

[ibc]

This PR exposes kernel mayor number in the mediasoup-worker binary name to make it possible to have prebuilts for Linux with kernel 5 and 6 (the latter supports io-uring).

NOTE 1: This is related to issue #1282 but doesn't complete it.

TODO: In mediasoup-worker-prebuild.yaml we must include an Ubuntu version with kernel >= 6. Problem is that Ubuntu 22.04 still uses kernel 5.15 and there are no other more modern Ubuntu versions in GitHub CI.

NOTE 2: When that is done (in part 2 of this task), we must still keep Ubuntu 20.04 since, as documented in the job file, it uses an older version of GLib and otherwise we'd run into this issue again: #1089.

[nazar-pc]

I'm not opposed to merging this, but major version doesn't really mean anything in Linux. And there is a pretty wild range of features available between various revisions of each major version.

I think this will have to become more sophisticated over time to make sure proper versions are accounted for.

I'm also wondering how hard it would be to compile a worker that can make decision about whether to enable io_uring in runtime.

Then it would be possible to install kernel headers and such from newer version even on older kernel and compile it with io_uring support on 20.04, while not using it in runtime if kernel is too old.

[ibc]

I'm not opposed to merging this, but major version doesn't really mean anything in Linux. And there is a pretty wild range of features available between various revisions of each major version.

I think this will have to become more sophisticated over time to make sure proper versions are accounted for.

I'm also wondering how hard it would be to compile a worker that can make decision about whether to enable io_uring in runtime.

Then it would be possible to install kernel headers and such from newer version even on older kernel and compile it with io_uring support on 20.04, while not using it in runtime if kernel is too old.

• meson.build only compiles liburing subproject if current host has kernel >6. Why? Because liburing depends on io-uring which is only available in Linux kernel >= 6.
• Then in DepLibUring.IsRuntimeSupported() (so in runtime) we verify whether current running host has kernel >= 6, otherwise we do not use liburing subproject.

In summary:

1. liburing can only be built if the host in which the worker is built has kernel > 6.
2. Later that mediasoup-worker prebuilt could work in a kernel 5. In that case liburing is disabled in runtime.
3. Bullet 1 is a requirement for bullet 2.

[nazar-pc]

liburing can only be built if the host in which the worker is built has kernel > 6.

I do not necessarily think that is the case. Headers from newer kernel are probably required, but the kernel running as such. It can be installed on a system running older kernel and with some tweaks to default library search paths compiler should be able to see it.

[ibc]

liburing can only be built if the host in which the worker is built has kernel > 6.

I do not necessarily think that is the case. Headers from newer kernel are probably required, but the kernel running as such. It can be installed on a system running older kernel and with some tweaks to default library search paths compiler should be able to see it.

Not sure why such a effort is needed. We only need a kernel >= 6 in CI which is not available yet.

[nazar-pc]

I'm fine with this, just exploring possibilities

[ibc]

NOTE: as a side effect of this PR part 1, those installing mediasoup node in Debian or Ubuntu or RedHat etc with kernel >= 6 will not have prebuilt worker available so will build worker from scratch, and hence with io-uring support, which IMHO is good. What do you think @jmillan?

[jmillan]

I think this should not be needed. Once GH action runners run kernel 6 liburing will be built automatically. Until that happens (unless we manage to compile it with proper headers from an older linux) then liburing will be disabled in the prebuilt binaries.

How will this PR help in any way?

[ibc]

I think this should not be needed. Once GH action runners run kernel 6 liburing will be built automatically. Until that happens (unless we manage to compile it with proper headers from an older linux) then liburing will be disabled in the prebuilt binaries.

How will this PR help in any way?

1. We need a worker prebuilt made with Ubuntu 20.04 due to the GLib issue (see the link in the PR description), so it can work in not super recent Linux hosts, let's say those running kernel 5 (hopefully).
2. This PR forces new Linux hosts (with kernel 6) to compile worker from scratch since there won't be (yet) prebuilt for them, so the worker will support io-uring.

[jmillan]

I think this should not be needed. Once GH action runners run kernel 6 liburing will be built automatically. Until that happens (unless we manage to compile it with proper headers from an older linux) then liburing will be disabled in the prebuilt binaries.

How will this PR help in any way?

1. We need a worker prebuilt made with Ubuntu 20.04 due to the GLib issue (see the link in the PR description), so it can work in not super recent Linux hosts, let's say those running kernel 5 (hopefully).
2. This PR forces new Linux hosts (with kernel 6) to compile worker from scratch since there won't be (yet) prebuilt for them, so the worker will support io-uring.

Gotcha, rather than renaming the binary with the kernel version I think a more elegant way is that the binary itself can tell it, via command argument. Ie: mediasoup-worker -v [--version] or --info. The output of that command being, among others, whether io_uring is built-in.

[ibc]

Gotcha, rather than renaming the binary with the kernel version I think a more elegant way is that the binary itself can tell it, via command argument. Ie: mediasoup-worker -v [--version] or --info. The output of that command being, among others, whether io_uring is built-in.

For what? How would that help? And how is that related to the prebuilt fetching?

[jmillan]

Anyway I'm OK with this change.

[ibc]

Imagine we had Ubuntu 24.04 with kernel 6 in GitHub actions so we can produce io-using capable worker. But we still need to produce a prebuilt worker for Linux with older GLib (due to the referenced issue). So we need TWO prebuilt binaries so two different names. This is not about having "npm install mediasoup" downloading a "universal" binary and then checking some command on it to see if it was valid or not.

[nazar-pc]

I agree, we do want to be able to make decision before downloading