perf data: Add JSON export

This adds a feature to export perf data to JSON. The resolved symbols are exported into the JSON so that external tools don't need to load the dsos themselves (or even have access to them at all.) This makes it easy to load and analyze perf data with standalone tools where direct perf or libbabeltrace integration is impractical. The exporter uses a minimal inline JSON encoding without any external dependencies. Currently it only outputs some headers and sample metadata but it's easily extensible. Use it like this: $ perf data convert --to-json out.json Committer notes: Fixup a __printf() bug that broke the build: util/data-convert-json.c:103:11: error: expected ‘)’ before numeric constant 103 | __(printf, 5, 6) | ^~ | ) util/data-convert-json.c: In function ‘output_sample_callchain_entry’: util/data-convert-json.c:124:2: error: implicit declaration of function ‘output_json_key_format’; did you mean ‘output_json_format’? [-Werror=implicit-function-declaration] 124 | output_json_key_format(out, false, 5, "ip", "\"0x%" PRIx64 "\"", ip); | ^~~~~~~~~~~~~~~~~~~~~~ | output_json_format Also had to add this patch to fix errors reported by various versions of clang: - if (al && al->sym && al->sym->name && strlen(al->sym->name) > 0) { + if (al && al->sym && al->sym->namelen) { al->sym->name is a zero sized array, to avoid one extra alloc in the symbol__new() constructor, sym->namelen carries its strlen. Committer testing: $ ls -la out.json ls: cannot access 'out.json': No such file or directory $ perf record sleep 0.1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.001 MB perf.data (8 samples) ] $ perf report --stats | grep -w SAMPLE SAMPLE events: 8 $ perf data convert --to-json out.json [ perf data convert: Converted 'perf.data' into JSON data 'out.json' ] [ perf data convert: Converted and wrote 0.002 MB (8 samples) ] $ ls -la out.json -rw-rw-r--. 1 acme acme 2017 Apr 26 17:29 out.json $ cat out.json { "linux-perf-json-version": 1, "headers": { "header-version": 1, "captured-on": "2021-04-26T20:28:57Z", "data-offset": 432, "data-size": 1016, "feat-offset": 1448, "hostname": "five", "os-release": "5.11.14-200.fc33.x86_64", "arch": "x86_64", "cpu-desc": "AMD Ryzen 9 3900X 12-Core Processor", "cpuid": "AuthenticAMD,23,113,0", "nrcpus-online": 24, "nrcpus-avail": 24, "perf-version": "5.12.gee134f3189bd", "cmdline": [ "/home/acme/bin/perf", "record", "sleep", "0.1" ] }, "samples": [ { "timestamp": 170517539043684, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0xffffffffa6268827" } ] }, { "timestamp": 170517539048443, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0xffffffffa661359d" } ] }, { "timestamp": 170517539051018, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0xffffffffa6311e18" } ] }, { "timestamp": 170517539053652, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0x7fdb77b4812b", "symbol": "_dl_start", "dso": "ld-2.32.so" } ] }, { "timestamp": 170517539055306, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0xffffffffa6269286" } ] }, { "timestamp": 170517539057590, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0xffffffffa62abd8b" } ] }, { "timestamp": 170517539067559, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0x7fdb77b5e9e9", "symbol": "__GI___tunables_init", "dso": "ld-2.32.so" } ] }, { "timestamp": 170517539282452, "pid": 375844, "tid": 375844, "comm": "sleep", "callchain": [ { "ip": "0x7fdb779978d2", "symbol": "getenv", "dso": "libc-2.32.so" } ] } ] } $ Signed-off-by: Nicholas Fraser <nfraser@codeweavers.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Changbin Du <changbin.du@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tan Xiaojun <tanxiaojun@huawei.com> Cc: Ulrich Czekalla <uczekalla@codeweavers.com> Link: http://lore.kernel.org/lkml/3884969f-804d-2f53-c648-e2b0bd85edff@codeweavers.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
mariux64 · Apr 29, 2021 · d0713d4 · d0713d4
1 parent 5508c9d
commit d0713d4
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diff --git a/tools/perf/Documentation/perf-data.txt b/tools/perf/Documentation/perf-data.txt
@@ -17,7 +17,7 @@ Data file related processing.
 COMMANDS
 --------
 convert::
-	Converts perf data file into another format (only CTF [1] format is support by now).
+	Converts perf data file into another format.
 	It's possible to set data-convert debug variable to get debug messages from conversion,
 	like:
 	  perf --debug data-convert data convert ...
@@ -27,6 +27,9 @@ OPTIONS for 'convert'
 --to-ctf::
 	Triggers the CTF conversion, specify the path of CTF data directory.
 
+--to-json::
+	Triggers JSON conversion. Specify the JSON filename to output.
+
 --tod::
 	Convert time to wall clock time.
 

diff --git a/tools/perf/builtin-data.c b/tools/perf/builtin-data.c
@@ -7,7 +7,6 @@
 #include "debug.h"
 #include <subcmd/parse-options.h>
 #include "data-convert.h"
-#include "data-convert-bt.h"
 
 typedef int (*data_cmd_fn_t)(int argc, const char **argv);
 
@@ -55,14 +54,16 @@ static const char * const data_convert_usage[] = {
 
 static int cmd_data_convert(int argc, const char **argv)
 {
-	const char *to_ctf     = NULL;
+	const char *to_json = NULL;
+	const char *to_ctf = NULL;
 	struct perf_data_convert_opts opts = {
 		.force = false,
 		.all = false,
 	};
 	const struct option options[] = {
 		OPT_INCR('v', "verbose", &verbose, "be more verbose"),
 		OPT_STRING('i', "input", &input_name, "file", "input file name"),
+		OPT_STRING(0, "to-json", &to_json, NULL, "Convert to JSON format"),
 #ifdef HAVE_LIBBABELTRACE_SUPPORT
 		OPT_STRING(0, "to-ctf", &to_ctf, NULL, "Convert to CTF format"),
 		OPT_BOOLEAN(0, "tod", &opts.tod, "Convert time to wall clock time"),
@@ -72,23 +73,32 @@ static int cmd_data_convert(int argc, const char **argv)
 		OPT_END()
 	};
 
-#ifndef HAVE_LIBBABELTRACE_SUPPORT
-	pr_err("No conversion support compiled in. perf should be compiled with environment variables LIBBABELTRACE=1 and LIBBABELTRACE_DIR=/path/to/libbabeltrace/\n");
-	return -1;
-#endif
-
 	argc = parse_options(argc, argv, options,
 			     data_convert_usage, 0);
 	if (argc) {
 		usage_with_options(data_convert_usage, options);
 		return -1;
 	}
 
+	if (to_json && to_ctf) {
+		pr_err("You cannot specify both --to-ctf and --to-json.\n");
+		return -1;
+	}
+	if (!to_json && !to_ctf) {
+		pr_err("You must specify one of --to-ctf or --to-json.\n");
+		return -1;
+	}
+
+	if (to_json)
+		return bt_convert__perf2json(input_name, to_json, &opts);
+
 	if (to_ctf) {
 #ifdef HAVE_LIBBABELTRACE_SUPPORT
 		return bt_convert__perf2ctf(input_name, to_ctf, &opts);
 #else
-		pr_err("The libbabeltrace support is not compiled in.\n");
+		pr_err("The libbabeltrace support is not compiled in. perf should be "
+		       "compiled with environment variables LIBBABELTRACE=1 and "
+		       "LIBBABELTRACE_DIR=/path/to/libbabeltrace/\n");
 		return -1;
 #endif
 	}

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
@@ -165,6 +165,7 @@ perf-$(CONFIG_LIBUNWIND_X86)      += libunwind/x86_32.o
 perf-$(CONFIG_LIBUNWIND_AARCH64)  += libunwind/arm64.o
 
 perf-$(CONFIG_LIBBABELTRACE) += data-convert-bt.o
+perf-y += data-convert-json.o
 
 perf-y += scripting-engines/
 

diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
@@ -21,7 +21,7 @@
 #include <babeltrace/ctf/events.h>
 #include <traceevent/event-parse.h>
 #include "asm/bug.h"
-#include "data-convert-bt.h"
+#include "data-convert.h"
 #include "session.h"
 #include "debug.h"
 #include "tool.h"

diff --git a/tools/perf/util/data-convert-bt.h b/tools/perf/util/data-convert-bt.h