Em Mon, Nov 16, 2020 at 08:40:08PM +0100, Jiri Olsa escreveu: > On Mon, Nov 16, 2020 at 04:22:21PM -0300, Arnaldo Carvalho de Melo wrote: > > Em Mon, Nov 16, 2020 at 04:15:44PM -0300, Arnaldo Carvalho de Melo escreveu: > > > Em Mon, Nov 16, 2020 at 07:21:45PM +0100, Jiri Olsa escreveu: > > > > On Mon, Nov 16, 2020 at 10:50:16AM -0300, Arnaldo Carvalho de Melo wrote: > > > > > Em Fri, Nov 13, 2020 at 01:43:47PM -0800, Andrii Nakryiko escreveu: > > > > > > On Fri, Nov 13, 2020 at 1:29 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > > > > > > > > > > > On Fri, Nov 13, 2020 at 12:56:40PM -0800, Andrii Nakryiko wrote: > > > > > > > > On Fri, Nov 13, 2020 at 7:13 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > Current conditions for picking up function records break > > > > > > > > > BTF data on some gcc versions. > > > > > > > > > > > > > > Some function records can appear with no arguments but with > > > > > > > > > declaration tag set, so moving the 'fn->declaration' in front > > > > > > > > > of other checks. > > > > > > > > > > > > > > Then checking if argument names are present and finally checking > > > > > > > > > ftrace filter if it's present. If ftrace filter is not available, > > > > > > > > > using the external tag to filter out non external functions. > > > > > > > > > > > > > > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> > > > > > > > > > > > > > I tested locally, all seems to work fine. Left few suggestions below, > > > > > > > > but those could be done in follow ups (or argued to not be done). > > > > > > > > > > > > > Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > > > > > > > > > > > > > BTW, for some stats. > > > > > > > > > > > > > BEFORE allowing static funcs: > > > > > > > > > > > > > > > Nowhere in the last patchkit comments is some explanation for the > > > > > inclusion of static functions :-\ After the first patch in the last > > > > > series I get: > > > > > > > > > > $ llvm-objcopy --remove-section=.BTF vmlinux > > > > > $ readelf -SW vmlinux | grep BTF > > > > > $ pahole -J vmlinux > > > > > $ bpftool btf dump file ./vmlinux | grep 'FUNC '| cut -d\' -f2 | sort > before.bpftool > > > > > $ cp vmlinux vmlinux.before.all > > > > > $ wc -l before.bpftool > > > > > 28829 before.bpftool > > > > > > > > I think you see the original number of functions, because without > > > > the 'not merged' kernel patch, that added the special init section, > > > > pahole will fail to detect vmlinux and fall back to checking dwarf > > > > declarations > > > > > > Indeed, I moved the verbose/force setting to the beggining of the > > > encoder and: > > > > > > ------------ > > > Found 352 per-CPU variables! > > > vmlinux not detected, falling back to dwarf data > > > File vmlinux: > > > search cu '/home/acme/git/linux/arch/x86/kernel/head_64.S' for percpu global variables. > > > ----------------- > > > > > > Now I have to read that code to figure out what that "vmlinux not > > > detected, falling back to dwarf data" message means, as vmlinux is where > > > DWARF data is, so what is that isn't being "detected", /me checks... > > > > So with some debugging I see, the message is just confusing: > > > > "vmlinux not detected, falling back to dwarf data (functions_cnt=53238, has_all_symbols(&fl)=0" > > how about: > > "ftrace data not detected, falling back to dwarf data" Much better! > > > > It finds the ELF symtab, finds the percpu variables there, tons of > > functions, matching the number after this approach of marking BPF init > > functions was dropped its just that vague "has_all_symbols()" routine > > that fails to find all the symbols it needs in the vmlinux file. > > we collect functions and other symbols in one loop over the symtab, > so thats why we have all those collected and still can decide to fall back > > before we needed also the init section symbols, now with this patch > we need to know only mcount section begin/end Thanks for the explanations, match my observations, its just that the functions could have some more descriptive names :) Please send the patch with the s/vmlinux/ftrace symbols/g and please also s/dwarf/DWARF/g as its an acronym. - Arnaldo
