From ccd26741f5e6bdf2c18ea38b32e6a347c5648a97 Mon Sep 17 00:00:00 2001 From: Ravi Bangoria Date: Fri, 8 Nov 2019 15:11:28 +0530 Subject: perf tool: Provide an option to print perf_event_open args and return value Perf record with verbose=2 already prints this information along with whole lot of other traces which requires lot of scrolling. Introduce an option to print only perf_event_open() arguments and return value. Sample o/p: $ perf --debug perf-event-open=1 record -- ls > /dev/null ------------------------------------------------------------ perf_event_attr: size 112 { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|PERIOD read_format ID disabled 1 inherit 1 exclude_kernel 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 precise_ip 3 sample_id_all 1 exclude_guest 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 ------------------------------------------------------------ sys_perf_event_open: pid 4308 cpu 0 group_fd -1 flags 0x8 = 4 sys_perf_event_open: pid 4308 cpu 1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 4308 cpu 2 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid 4308 cpu 3 group_fd -1 flags 0x8 = 8 sys_perf_event_open: pid 4308 cpu 4 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid 4308 cpu 5 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid 4308 cpu 6 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid 4308 cpu 7 group_fd -1 flags 0x8 = 12 ------------------------------------------------------------ perf_event_attr: type 1 size 112 config 0x9 watermark 1 sample_id_all 1 bpf_event 1 { wakeup_events, wakeup_watermark } 1 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.002 MB perf.data (9 samples) ] Committer notes: Just like the 'verbose' variable this new 'debug_peo_args' needs to be added to util/python.c, since we don't link the debug.o file in the python binding, which ended up making 'perf test python' fail with: # perf test -v python 18: 'import perf' in python : --- start --- test child forked, pid 19237 Traceback (most recent call last): File "", line 1, in ImportError: /tmp/build/perf/python/perf.so: undefined symbol: debug_peo_args test child finished with -1 ---- end ---- 'import perf' in python: FAILED! # After adding that new variable to util/python.c: # perf test -v python 18: 'import perf' in python : --- start --- test child forked, pid 22364 test child finished with 0 ---- end ---- 'import perf' in python: Ok # Signed-off-by: Ravi Bangoria Tested-by: Arnaldo Carvalho de Melo Acked-by: Jiri Olsa Link: http://lore.kernel.org/lkml/20191108094128.28769-1-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'tools/perf/Documentation') diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt index 401f0ed67439..3f37ded13f8c 100644 --- a/tools/perf/Documentation/perf.txt +++ b/tools/perf/Documentation/perf.txt @@ -24,6 +24,8 @@ OPTIONS data-convert - data convert command debug messages stderr - write debug output (option -v) to stderr in browser mode + perf-event-open - Print perf_event_open() arguments and + return value --buildid-dir:: Setup buildid cache directory. It has higher priority than -- cgit v1.2.3