On Wed, 2021-03-10 at 10:37 -0300, Arnaldo Carvalho de Melo wrote: > Em Tue, Mar 09, 2021 at 08:14:50PM -0800, Andrii Nakryiko escreveu: > > On Tue, Mar 9, 2021 at 1:57 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> > > wrote: > > > On Tue, 2021-03-09 at 13:37 -0800, Andrii Nakryiko wrote: > > > > On Tue, Mar 9, 2021 at 3:48 AM Arnaldo Carvalho de Melo > > > > <acme@xxxxxxxxxx> wrote: > > > > > Em Tue, Mar 09, 2021 at 12:59:13AM +0100, Ilya Leoshkevich > > > > > escreveu: > > > > TBH, I think it's not exactly right to call out libbpf version > > > > here. It's BTF "version" (if we had such a thing) that > > > > determines > > > > the set of supported BTF kinds. There could be other libraries > > > > that might want to parse BTF. So I don't know what this should > > > > be > > > > called, but libbpf_compat is probably a wrong name for it. > > > > BTF version seems to exist: btf_header.version. Should we maybe > > > bump > > > this? > > > That seems excessive. If the kernel doesn't use FLOATs, then no one > > would even notice a difference. While if we bump this version, then > > everything will automatically become incompatible. > > > > > If we do want to teach pahole to not emit some parts of BTF, it > > > > should > > > > probably be a set of BPF features, not some arbitrary library > > > > versions. > > > > I thought about just adding --btf-allow-floats, but if new > > > features > > > will be added in the future, the list of options will become > > > unwieldy. > > > So I thought it would be good to settle for something that > > > increases > > > monotonically. > > > BTF_KIND_FLOAT is the first extension in a long while. I'd worry > > about > > the proliferation of new options when we actually see some proof of > > that being a problem in practice. > > I tend to agree, Ilya, can you rework the patch in that direction? > Something like --encode-btf-kind-float that starts disabled or other > suitable name? > > - Arnaldo Sure, I'm actually testing v3 that does this right now. So far I went with simply --btf_float, but I'll change it to the more explicit --encode_btf_kind_float.
