From d0713d4ca3e94827de77f8758e3e8045a0d85215 Mon Sep 17 00:00:00 2001 From: Nicholas Fraser Date: Mon, 26 Apr 2021 10:47:16 -0400 Subject: perf data: Add JSON export MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Changbin Du Cc: Ian Rogers Cc: Jin Yao Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Tan Xiaojun Cc: Ulrich Czekalla Link: http://lore.kernel.org/lkml/3884969f-804d-2f53-c648-e2b0bd85edff@codeweavers.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-data.txt | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'tools/perf/Documentation') diff --git a/tools/perf/Documentation/perf-data.txt b/tools/perf/Documentation/perf-data.txt index 726b9bc9e1a7..417bf17e265c 100644 --- 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. -- cgit v1.2.3