Hi, On arm, probably since "ARM: use linker magic for vectors and vector stubs" (although I haven't checked this), perf report tends to allocate all kernel time to the module loaded at the highest address.
This turns out to be because the "perf_event__synthesize_modules" generates a PERF_RECORD_MMAP for the last module thats runs from its start to the end of the address space. This in turn turns out be because the first symbol in /proc/kallsyms is now at 0: # head -n 2 /proc/kallsyms 00000000 t __vectors_start c00081c0 T asm_do_IRQ /This/ means that the kallsyms entry in machine->kmaps[MAP__FUNCTION] is now the first entry rather than the last in the map, so the last module is the last in the map and so its "end" stays as ~0ULL. I'm told that there is no particularly good reason for __vectors_start to be in kallsyms at 0, but in any case this seems like a bug in the user space tool. I notice that there is code to split the kallsyms symbols around symbols from modules (dso__split_kallsyms) but this doesn't seem to be called for record, only report. Is the fix as simple as making sure this happens for record as well? I don't feel qualified to answer that. Cheers, mwh -- 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/
