提交 763122ad 编写于 作者: A Avi Kivity 提交者: Arnaldo Carvalho de Melo

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: NJiri Olsa <jolsa@redhat.com>
Signed-off-by: NAvi Kivity <avi@cloudius-systems.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1410581705-26968-1-git-send-email-avi@cloudius-systems.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
上级 29a3ce31
......@@ -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.
......
......@@ -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
......
......@@ -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.
......
......@@ -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;
......
......@@ -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),
......
......@@ -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",
......
......@@ -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 @@ int dso__load_sym(struct dso *dso, struct map *map,
* 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;
......
......@@ -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 = "",
......
......@@ -120,6 +120,7 @@ struct symbol_conf {
annotate_src,
event_group,
demangle,
demangle_kernel,
filter_relative,
show_hist_headers;
const char *vmlinux_name,
......
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