Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: [PATCH] perf: Ignore stripped vmlinux and fallback to kallsyms | Date | Fri, 12 Sep 2014 15:33:20 +0900 |
| |
Hi Anton,
On Tue, 9 Sep 2014 08:59:29 +1000, Anton Blanchard wrote: > If a vmlinux is stripped, perf will use it and ignore kallsyms. We > end up with useless profiles where everything maps to a few > runtime symbols: > > 63.39% swapper [kernel.kallsyms] [k] hcall_real_table > 4.90% beam.smp [kernel.kallsyms] [k] hcall_real_table > 4.44% beam.smp [kernel.kallsyms] [k] __sched_text_start > 3.72% beam.smp [kernel.kallsyms] [k] __run_at_kexec > > Detect this case and fallback to using kallsyms. This fixes the issue: > > 62.81% swapper [kernel.kallsyms] [k] snooze_loop > 4.44% beam.smp [kernel.kallsyms] [k] __schedule > 0.91% beam.smp [kernel.kallsyms] [k] _switch > 0.73% beam.smp [kernel.kallsyms] [k] put_prev_entity > > Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks, Namhyung
> --- > > Index: b/tools/perf/util/symbol-elf.c > =================================================================== > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -712,6 +712,14 @@ int dso__load_sym(struct dso *dso, struc > symbols__delete(&dso->symbols[map->type]); > > if (!syms_ss->symtab) { > + /* > + * If the vmlinux is stripped, fail so we will fall back > + * to using kallsyms. The vmlinux runtime symbols aren't > + * of much use. > + */ > + if (dso->kernel) > + goto out_elf_end; > + > syms_ss->symtab = syms_ss->dynsym; > syms_ss->symshdr = syms_ss->dynshdr; > }
| |