linux-kernel - Re: [PATCH v2 2/9] perf script: Add options for custom vdso path

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Date:	Wed, 11 May 2016 09:33:31 +0800
From:	Hekuang <hekuang@...wei.com>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
CC:	<peterz@...radead.org>, <mingo@...hat.com>,
	<alexander.shishkin@...ux.intel.com>, <jolsa@...hat.com>,
	<wangnan0@...wei.com>, <jpoimboe@...hat.com>, <ak@...ux.intel.com>,
	<eranian@...gle.com>, <namhyung@...nel.org>,
	<adrian.hunter@...el.com>, <sukadev@...ux.vnet.ibm.com>,
	<masami.hiramatsu.pt@...achi.com>, <tumanova@...ux.vnet.ibm.com>,
	<kan.liang@...el.com>, <penberg@...nel.org>, <dsahern@...il.com>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/9] perf script: Add options for custom vdso path



在 2016/5/10 21:44, Arnaldo Carvalho de Melo 写道:
> Em Tue, May 10, 2016 at 07:40:30AM +0000, He Kuang escreveu:
>> When unwinding callchains on a different machine, vdso info should be
>> provided so the unwind process won't be interrupted if address falls
>> into vdso region.
>>
>> Currently, perf does try to read vdso binary in '.debug' folder, but
>> the filename of the vdso file is generated randomly based on
>> VDSO__TEMP_FILE_NAME template, such a filename is not reliable and
>> users need a way to provide the path of their own vdso binary file.
> But this becomes one more burden to the user :-\ Why not calculate a
> build-id from the VDSO file contents, copy it to
> ~/.debug/.build-id/ab/cdef01020304 and insert that into the perf.data
> file so that at analysis time we do all this automatically?
>
> We can of course have a way to manually provide it, but having it as the
> main way for users doesn't seem a good interface. Am I missing
> something?
>
> - Arnaldo

OK, I'll try as you suggested!
>   
>> Signed-off-by: He Kuang <hekuang@...wei.com>
>> ---
>>   tools/perf/builtin-script.c | 2 ++
>>   tools/perf/util/dso.c       | 7 +++++++
>>   tools/perf/util/dso.h       | 1 +
>>   tools/perf/util/symbol.c    | 1 +
>>   tools/perf/util/symbol.h    | 1 +
>>   5 files changed, 12 insertions(+)
>>
>> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
>> index 8f6ab2a..c88b547 100644
>> --- a/tools/perf/builtin-script.c
>> +++ b/tools/perf/builtin-script.c
>> @@ -2001,6 +2001,8 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
>>   		   "file", "vmlinux pathname"),
>>   	OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
>>   		   "file", "kallsyms pathname"),
>> +	OPT_STRING(0, "vdso", &symbol_conf.vdso_name,
>> +		   "file", "vdso pathname"),
>>   	OPT_BOOLEAN('G', "hide-call-graph", &no_callchain,
>>   		    "When printing symbols do not display call chain"),
>>   	OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
>> diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
>> index 8e639543..6ed1cce 100644
>> --- a/tools/perf/util/dso.c
>> +++ b/tools/perf/util/dso.c
>> @@ -13,6 +13,7 @@ char dso__symtab_origin(const struct dso *dso)
>>   	static const char origin[] = {
>>   		[DSO_BINARY_TYPE__KALLSYMS]			= 'k',
>>   		[DSO_BINARY_TYPE__VMLINUX]			= 'v',
>> +		[DSO_BINARY_TYPE__VDSO]				= 'D',
>>   		[DSO_BINARY_TYPE__JAVA_JIT]			= 'j',
>>   		[DSO_BINARY_TYPE__DEBUGLINK]			= 'l',
>>   		[DSO_BINARY_TYPE__BUILD_ID_CACHE]		= 'B',
>> @@ -113,6 +114,11 @@ int dso__read_binary_type_filename(const struct dso *dso,
>>   			 build_id_hex, build_id_hex + 2);
>>   		break;
>>   
>> +	case DSO_BINARY_TYPE__VDSO:
>> +	{
>> +		snprintf(filename, size, "%s", symbol_conf.vdso_name);
>> +		break;
>> +	}
>>   	case DSO_BINARY_TYPE__VMLINUX:
>>   	case DSO_BINARY_TYPE__GUEST_VMLINUX:
>>   	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
>> @@ -487,6 +493,7 @@ static void try_to_open_dso(struct dso *dso, struct machine *machine)
>>   	enum dso_binary_type binary_type_data[] = {
>>   		DSO_BINARY_TYPE__BUILD_ID_CACHE,
>>   		DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
>> +		DSO_BINARY_TYPE__VDSO,
>>   		DSO_BINARY_TYPE__NOT_FOUND,
>>   	};
>>   	int i = 0;
>> diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
>> index 0953280..05fac98 100644
>> --- a/tools/perf/util/dso.h
>> +++ b/tools/perf/util/dso.h
>> @@ -30,6 +30,7 @@ enum dso_binary_type {
>>   	DSO_BINARY_TYPE__KCORE,
>>   	DSO_BINARY_TYPE__GUEST_KCORE,
>>   	DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
>> +	DSO_BINARY_TYPE__VDSO,
>>   	DSO_BINARY_TYPE__NOT_FOUND,
>>   };
>>   
>> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
>> index e7588dc..4630751 100644
>> --- a/tools/perf/util/symbol.c
>> +++ b/tools/perf/util/symbol.c
>> @@ -1363,6 +1363,7 @@ static bool dso__is_compatible_symtab_type(struct dso *dso, bool kmod,
>>   	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
>>   	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
>>   	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
>> +	case DSO_BINARY_TYPE__VDSO:
>>   		return !kmod && dso->kernel == DSO_TYPE_USER;
>>   
>>   	case DSO_BINARY_TYPE__KALLSYMS:
>> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
>> index c8b7544..4e6910e 100644
>> --- a/tools/perf/util/symbol.h
>> +++ b/tools/perf/util/symbol.h
>> @@ -114,6 +114,7 @@ struct symbol_conf {
>>   			report_hierarchy;
>>   	const char	*vmlinux_name,
>>   			*kallsyms_name,
>> +			*vdso_name,
>>   			*source_prefix,
>>   			*field_sep;
>>   	const char	*default_guest_vmlinux_name,
>> -- 
>> 1.8.5.2