Em Mon, Nov 10, 2014 at 03:53:06PM +0900, Namhyung Kim escreveu: > On Fri, 7 Nov 2014 12:29:31 -0300, Arnaldo Carvalho de Melo wrote: > > Em Fri, Nov 07, 2014 at 02:20:04PM +0900, Namhyung Kim escreveu: > >> When libelf is not used, perf cannot not show symbol names since it > >> doesn't access the ELF symbol table. But kernel is different as it > >> can fallback to kallsyms.
> >> It worked w/o libelf, but recent change to use vmlinux for kernel > >> symbols break it. > >> With this change, it now can show kernel symbols again: > > Ok, but since you added that minimal ELF symtab loading, isn't better to > > try that first, i.e. if we find a vmlinux file with a build-id and with > > symbols in it... > > If that isn't the case, i.e. no vmlinux was found, then we fallback to > > kallsyms, to check if that is available. > > I.e. with your new minimalistic ELF symtab loader if we have a suitable > > vmlinux but no kallsyms, we end up resolving no symbols even having that > > nice vmlinux :-) > > Yeah, maybe. But it'd add a substantial complexity also and I tried to > make it simple and small only to show usual userspace symbols. > > I think that about a half of the complexity of the dso__load_sym() in > symbol-elf.c came from the kernel (and module) support. And expecting Right, I agree that thing grew too complex, reducing that complexity is something we should do when we have the chance. I.e. perhaps we could separate kernel/modules handling out of it, even if just at source code level at first... > kallsyms on the system is not a high barrier IMHO. So I decided to just > fall back to kallsyms for kernel dsos. Mayby we can add the kernel > support incrementally later. The suggestion came because you did that minimalistic reader, which if can be used for vmlinux files, would be great, as resolving vmlinux samples is such a major usecase :-) - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
