On Thu, Jul 28, 2022 at 7:33 AM Dirk Müller wrote:

Hi Jan,

Am Do., 28. Juli 2022 um 16:20 Uhr schrieb Jan Engelhardt :

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if we do not drop i586, there is no hole, as hardware incompatible with x86_64-v2 can still run i586. I like your thinking. We should set the distro level to x86_64-v4 then: Hardware incompatible with x86_64-v4 can still run the i586 binaries.

I hear the irony in this. Okay. let me rephrase:

a) select a base level (-v1 or -v2, don't really personally care, I have no -v1 only hardware anymore)

b) offer hwcaps overlay like -v3.

This makes sense to me. I don't think the majority of packages will benefit from -v3, but -v2 has been around long enough that it's generally fine and in-line with expected targeted systems.

I think -v4, which essentially requires AVX512 is likely not worth the effort except for some really extreme cases, where the open source projects in questions likely already have customized AVX512 assembly included that is executed when the hardware fits.

As long as Intel continues to segment instructions across CPUs and not include newer AVX instructions in even newly released processors, -v4 will never be realistic. -v3 is already problematic for similar reasons. -- 真実はいつも一つ！/ Always, there's only one truth!