From 763122ade725592402190f5ff3b8d2edf42b87e8 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sat, 13 Sep 2014 07:15:05 +0300 Subject: [PATCH] perf tools: Disable kernel symbol demangling by default Some Linux symbols (for example __vt_event_wait) are interpreted by the demangler as C++ mangled names, which of course they aren't. Disable kernel symbol demangling by default to avoid this, and allow enabling it with a new option --demangle-kernel for those who wish it. Reported-by: Jiri Olsa Signed-off-by: Avi Kivity Acked-by: Jiri Olsa Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1410581705-26968-1-git-send-email-avi@cloudius-systems.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-probe.txt | 3 +++ tools/perf/Documentation/perf-report.txt | 3 +++ tools/perf/Documentation/perf-top.txt | 3 +++ tools/perf/builtin-probe.c | 2 ++ tools/perf/builtin-report.c | 2 ++ tools/perf/builtin-top.c | 2 ++ tools/perf/util/symbol-elf.c | 7 ++++++- tools/perf/util/symbol.c | 1 + tools/perf/util/symbol.h | 1 + 9 files changed, 23 insertions(+), 1 deletion(-) diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt index 1513935c399b..aaa869be3dc1 100644 --- a/tools/perf/Documentation/perf-probe.txt +++ b/tools/perf/Documentation/perf-probe.txt @@ -104,6 +104,9 @@ OPTIONS Specify path to the executable or shared library file for user space tracing. Can also be used with --funcs option. +--demangle-kernel:: + Demangle kernel symbols. + In absence of -m/-x options, perf probe checks if the first argument after the options is an absolute path name. If its an absolute path, perf probe uses it as a target module/target user space binary to probe. diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt index d561e0214f52..0927bf4e6c2a 100644 --- a/tools/perf/Documentation/perf-report.txt +++ b/tools/perf/Documentation/perf-report.txt @@ -276,6 +276,9 @@ OPTIONS Demangle symbol names to human readable form. It's enabled by default, disable with --no-demangle. +--demangle-kernel:: + Demangle kernel symbol names to human readable form (for C++ kernels). + --mem-mode:: Use the data addresses of samples in addition to instruction addresses to build the histograms. To generate meaningful output, the perf.data diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt index 28fdee394880..3265b1070518 100644 --- a/tools/perf/Documentation/perf-top.txt +++ b/tools/perf/Documentation/perf-top.txt @@ -98,6 +98,9 @@ Default is to monitor all CPUS. --hide_user_symbols:: Hide user symbols. +--demangle-kernel:: + Demangle kernel symbols. + -D:: --dump-symtab:: Dump the symbol table used for profiling. diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c index 347729e29a92..4d6858dbebea 100644 --- a/tools/perf/builtin-probe.c +++ b/tools/perf/builtin-probe.c @@ -376,6 +376,8 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused) "target executable name or path", opt_set_target), OPT_BOOLEAN(0, "demangle", &symbol_conf.demangle, "Disable symbol demangling"), + OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel, + "Enable kernel symbol demangling"), OPT_END() }; int ret; diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 3da59a87ec7c..8c0b3f22412a 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -680,6 +680,8 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused) "objdump binary to use for disassembly and annotations"), OPT_BOOLEAN(0, "demangle", &symbol_conf.demangle, "Disable symbol demangling"), + OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel, + "Enable kernel symbol demangling"), OPT_BOOLEAN(0, "mem-mode", &report.mem_mode, "mem access profile"), OPT_CALLBACK(0, "percent-limit", &report, "percent", "Don't show entries under that percent", parse_percent_limit), diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 9848e270b92c..7da2c46ea38f 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -1142,6 +1142,8 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused) "Interleave source code with assembly code (default)"), OPT_BOOLEAN(0, "asm-raw", &symbol_conf.annotate_asm_raw, "Display raw encoding of assembly instructions (default)"), + OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel, + "Enable kernel symbol demangling"), OPT_STRING(0, "objdump", &objdump_path, "path", "objdump binary to use for disassembly and annotations"), OPT_STRING('M', "disassembler-style", &disassembler_style, "disassembler style", diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 9fb5e9e9f161..9c9b27fbc78d 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -680,6 +680,11 @@ static u64 ref_reloc(struct kmap *kmap) return 0; } +static bool want_demangle(bool is_kernel_sym) +{ + return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle; +} + int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss, struct symsrc *runtime_ss, symbol_filter_t filter, int kmodule) @@ -938,7 +943,7 @@ new_symbol: * DWARF DW_compile_unit has this, but we don't always have access * to it... */ - if (symbol_conf.demangle) { + if (want_demangle(dso->kernel || kmodule)) { int demangle_flags = DMGL_NO_OPTS; if (verbose) demangle_flags = DMGL_PARAMS | DMGL_ANSI; diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index ac098a3c2a31..1adb143867e3 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -34,6 +34,7 @@ struct symbol_conf symbol_conf = { .try_vmlinux_path = true, .annotate_src = true, .demangle = true, + .demangle_kernel = false, .cumulate_callchain = true, .show_hist_headers = true, .symfs = "", diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h index 3f95ea0357e3..bec4b7bd09de 100644 --- a/tools/perf/util/symbol.h +++ b/tools/perf/util/symbol.h @@ -120,6 +120,7 @@ struct symbol_conf { annotate_src, event_group, demangle, + demangle_kernel, filter_relative, show_hist_headers; const char *vmlinux_name, -- 2.20.1