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charset=us-ascii Content-Disposition: inline In-Reply-To: <20191210100536.7a57d5e1@cakuba.netronome.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 12/10, Jakub Kicinski wrote: > On Tue, 10 Dec 2019 09:11:31 -0800, Andrii Nakryiko wrote: > > On Mon, Dec 9, 2019 at 5:57 PM Jakub Kicinski wrote: > > > On Mon, 9 Dec 2019 17:14:34 -0800, Andrii Nakryiko wrote: > > > > struct { > > > > /* used by libbpf's skeleton API */ > > > > struct bpf_object_skeleton *skeleton; > > > > /* bpf_object for libbpf APIs */ > > > > struct bpf_object *obj; > > > > struct { > > > > /* for every defined map in BPF object: */ > > > > struct bpf_map *; > > > > } maps; > > > > struct { > > > > /* for every program in BPF object: */ > > > > struct bpf_program *; > > > > } progs; > > > > struct { > > > > /* for every program in BPF object: */ > > > > struct bpf_link *; > > > > } links; > > > > /* for every present global data section: */ > > > > struct __ { > > > > /* memory layout of corresponding data section, > > > > * with every defined variable represented as a struct field > > > > * with exactly the same type, but without const/volatile > > > > * modifiers, e.g.: > > > > */ > > > > int *my_var_1; > > > > ... > > > > } *; > > > > }; > > > > > > I think I understand how this is useful, but perhaps the problem here > > > is that we're using C for everything, and simple programs for which > > > loading the ELF is majority of the code would be better of being > > > written in a dynamic language like python? Would it perhaps be a > > > better idea to work on some high-level language bindings than spend > > > time writing code gens and working around limitations of C? > > > > None of this work prevents Python bindings and other improvements, is > > it? Patches, as always, are greatly appreciated ;) > > This "do it yourself" shit is not really funny :/ > > I'll stop providing feedback on BPF patches if you guy keep saying > that :/ Maybe that's what you want. > > > This skeleton stuff is not just to save code, but in general to > > simplify and streamline working with BPF program from userspace side. > > Fortunately or not, but there are a lot of real-world applications > > written in C and C++ that could benefit from this, so this is still > > immensely useful. selftests/bpf themselves benefit a lot from this > > work, see few of the last patches in this series. > > Maybe those applications are written in C and C++ _because_ there > are no bindings for high level languages. I just wish BPF programming > was less weird and adding some funky codegen is not getting us closer > to that goal. > > In my experience code gen is nothing more than a hack to work around > bad APIs, but experiences differ so that's not a solid argument. *nod* We have a nice set of C++ wrappers around libbpf internally, so we can do something like BpfMap and get a much better interface with type checking. Maybe we should focus on higher level languages instead? We are open to open-sourcing our C++ bits if you want to collaborate. (I assume most of the stuff you have at fb is also non-c and one of c++/python/php/rust/go/whatver).