Messages in this thread Patch in this message | | | From | Namhyung Kim <> | Subject | [PATCH 1/3] perf tools: Allow vmlinux to fallback to kallsyms on NO_LIBELF=1 | Date | Fri, 7 Nov 2014 14:20:04 +0900 |
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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:
# Overhead Command Shared Object Symbol # ........ ....... ................. ........................ # 34.51% swapper [kernel.kallsyms] [k] intel_idle 12.54% perf [kernel.kallsyms] [k] generic_exec_single 10.11% swapper [kernel.kallsyms] [k] int_sqrt 9.83% swapper [kernel.kallsyms] [k] hrtimer_interrupt 7.25% emacs [kernel.kallsyms] [k] __switch_to 7.06% sleep [kernel.kallsyms] [k] find_next_iomem_res 7.02% swapper [kernel.kallsyms] [k] run_timer_softirq 2.55% swapper [kernel.kallsyms] [k] _raw_spin_unlock_irq 1.90% swapper [kernel.kallsyms] [k] lapic_next_deadline 1.75% swapper [kernel.kallsyms] [k] native_sched_clock 1.49% swapper [kernel.kallsyms] [k] __schedule 1.20% swapper [kernel.kallsyms] [k] read_tsc 1.10% sleep [kernel.kallsyms] [k] current_kernel_time 0.99% swapper [kernel.kallsyms] [k] pick_next_task_rt 0.36% swapper [kernel.kallsyms] [k] group_sched_in 0.24% swapper [kernel.kallsyms] [k] x86_pmu_commit_txn 0.06% swapper [kernel.kallsyms] [k] intel_pmu_enable_all 0.03% perf [kernel.kallsyms] [k] intel_pmu_enable_all
Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/util/symbol-minimal.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c index c9541fea9514..226cf41ed7e6 100644 --- a/tools/perf/util/symbol-minimal.c +++ b/tools/perf/util/symbol-minimal.c @@ -335,6 +335,9 @@ int dso__load_sym(struct dso *dso, struct map *map __maybe_unused, unsigned char *build_id[BUILD_ID_SIZE]; int ret; + if (dso->kernel) + return 0; /* always use kallsyms */ + ret = fd__is_64_bit(ss->fd); if (ret >= 0) dso->is_64_bit = ret; -- 2.1.2
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