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It seems like it takes just one user using a certain piece of hardware to justify it being supported in the kernel, which is surprising to me. The cost to kerne

by meisel 1y ago

It seems like it takes just one user using a certain piece of hardware to justify it being supported in the kernel, which is surprising to me. The cost to kernel dev velocity is not weighed more heavily against that?

hamandcheese 1y ago
Sometimes, supporting special use cases like this can be a valuable exercise since it shows you all the places in your project that you made assumptions without even realizing it. It seems plausible to me that supporting niche users improves quality of the project as a whole.
- kstrauser 1y ago
  To a point, yeah. Adding BE support to my (userspace) code revealed some bugs that affected LE, too. Oops! But you can take that too far, too. Like, go ahead and assume power-of-two aligned byte sizes. If someone wants to make an 11 bit byte, let them handle that in their own non-upstreamed fork. No user code’s going to work right on it anyway. You can be so flexible that it turns everything into a giant slog. I doubt 32 bit support is anywhere near that horrid; commenting on the idea more than this specific case.
bjackman 1y ago
In general I don't think the marginal benefit of removing support for a certain piece of hardware would be significant in most cases. Most of the kernel is generic across a broad enough spectrum that removing one slice of that spectrum isn't likely to change its breadth. E.g. there's some stuff like erratum workarounds for old x86 CPUs that would be nice to drop, but they are part of a big framework for handling x86 diversity. Dropping individual workarounds doesn't let you drop the framework. Exceptions are gonna be cases where dropping the support removed something significant from the lowest common denominator. Big stuff like word size, memory ordering (I assume dropping Alpha would be quite handy), virtual address space limitations.
SAI_Peregrinus 1y ago
One known user. Linux doesn't have automatic telemetry in every distro (or even most distros), the kernel devs don't really know how many people use. So if they know of one user, there are probably more users that just haven't come to their attention on the mailing lists.

by meisel 1y ago

hamandcheese 1y ago

Sometimes, supporting special use cases like this can be a valuable exercise since it shows you all the places in your project that you made assumptions without even realizing it. It seems plausible to me that supporting niche users improves quality of the project as a whole.

kstrauser 1y ago
To a point, yeah. Adding BE support to my (userspace) code revealed some bugs that affected LE, too. Oops! But you can take that too far, too. Like, go ahead and assume power-of-two aligned byte sizes. If someone wants to make an 11 bit byte, let them handle that in their own non-upstreamed fork. No user code’s going to work right on it anyway. You can be so flexible that it turns everything into a giant slog. I doubt 32 bit support is anywhere near that horrid; commenting on the idea more than this specific case.

bjackman 1y ago

In general I don't think the marginal benefit of removing support for a certain piece of hardware would be significant in most cases. Most of the kernel is generic across a broad enough spectrum that removing one slice of that spectrum isn't likely to change its breadth. E.g. there's some stuff like erratum workarounds for old x86 CPUs that would be nice to drop, but they are part of a big framework for handling x86 diversity. Dropping individual workarounds doesn't let you drop the framework. Exceptions are gonna be cases where dropping the support removed something significant from the lowest common denominator. Big stuff like word size, memory ordering (I assume dropping Alpha would be quite handy), virtual address space limitations.

SAI_Peregrinus 1y ago

One known user. Linux doesn't have automatic telemetry in every distro (or even most distros), the kernel devs don't really know how many people use. So if they know of one user, there are probably more users that just haven't come to their attention on the mailing lists.