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authorAdrian Hunter <adrian.hunter@intel.com>2020-04-01 13:16:13 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-04-18 15:05:00 +0300
commite345997914a8af5e8362e884d2fee38bd2e9c6d8 (patch)
tree06bfe7c6aeead42a7031e8048d3815f52edd2ca6 /tools/perf/Documentation/perf-list.txt
parent94d3820f2e18d3c88f833baec8d6ad5b3489fa59 (diff)
downloadlinux-e345997914a8af5e8362e884d2fee38bd2e9c6d8.tar.xz
perf tools: Add support for leader-sampling with AUX area events
When AUX area events are used in sampling mode, they must be the group leader, but the group leader is also used for leader-sampling. However, it is not desirable to use an AUX area event as the leader for leader-sampling, because it doesn't have any samples of its own. To support leader-sampling with AUX area events, use the 2nd event of the group as the "leader" for the purposes of leader-sampling. Example: # perf record --kcore --aux-sample -e '{intel_pt//,cycles,instructions}:S' -c 10000 uname [ perf record: Woken up 3 times to write data ] [ perf record: Captured and wrote 0.786 MB perf.data ] # perf report Samples: 380 of events 'anon group { cycles, instructions }', Event count (approx.): 3026164 Children Self Command Shared Object Symbol + 38.76% 42.65% 0.00% 0.00% uname [kernel.kallsyms] [k] __x86_indirect_thunk_rax + 35.82% 31.33% 0.00% 0.00% uname ld-2.28.so [.] _dl_start_user + 34.29% 29.74% 0.55% 0.47% uname ld-2.28.so [.] _dl_start + 33.73% 28.62% 1.60% 0.97% uname ld-2.28.so [.] dl_main + 33.19% 29.04% 0.52% 0.32% uname ld-2.28.so [.] _dl_sysdep_start + 27.83% 33.74% 0.00% 0.00% uname [kernel.kallsyms] [k] do_syscall_64 + 26.76% 33.29% 0.00% 0.00% uname [kernel.kallsyms] [k] entry_SYSCALL_64_after_hwframe + 23.78% 20.33% 5.97% 5.25% uname [kernel.kallsyms] [k] page_fault + 23.18% 24.60% 0.00% 0.00% uname libc-2.28.so [.] __libc_start_main + 22.64% 24.37% 0.00% 0.00% uname uname [.] _start + 21.04% 23.27% 0.00% 0.00% uname uname [.] main + 19.48% 18.08% 3.72% 3.64% uname ld-2.28.so [.] _dl_relocate_object + 19.47% 21.81% 0.00% 0.00% uname libc-2.28.so [.] setlocale + 19.44% 21.56% 0.52% 0.61% uname libc-2.28.so [.] _nl_find_locale + 17.87% 19.66% 0.00% 0.00% uname libc-2.28.so [.] _nl_load_locale_from_archive + 15.71% 13.73% 0.53% 0.52% uname [kernel.kallsyms] [k] do_page_fault + 15.18% 13.21% 1.03% 0.68% uname [kernel.kallsyms] [k] handle_mm_fault + 14.15% 12.53% 1.01% 1.12% uname [kernel.kallsyms] [k] __handle_mm_fault + 12.03% 9.67% 0.54% 0.32% uname ld-2.28.so [.] _dl_map_object + 10.55% 8.48% 0.00% 0.00% uname ld-2.28.so [.] openaux + 10.55% 20.20% 0.52% 0.61% uname libc-2.28.so [.] __run_exit_handlers Comnmitter notes: Fixed up this problem: util/record.c: In function ‘perf_evlist__config’: util/record.c:256:3: error: too few arguments to function ‘perf_evsel__config_leader_sampling’ 256 | perf_evsel__config_leader_sampling(evsel); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ util/record.c:190:13: note: declared here 190 | static void perf_evsel__config_leader_sampling(struct evsel *evsel, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lore.kernel.org/lkml/20200401101613.6201-17-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation/perf-list.txt')
-rw-r--r--tools/perf/Documentation/perf-list.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt
index 6345db33c533..cb23667531ab 100644
--- a/tools/perf/Documentation/perf-list.txt
+++ b/tools/perf/Documentation/perf-list.txt
@@ -258,6 +258,9 @@ Normally all events in an event group sample, but with :S only
the first event (the leader) samples, and it only reads the values of the
other events in the group.
+However, in the case AUX area events (e.g. Intel PT or CoreSight), the AUX
+area event must be the leader, so then the second event samples, not the first.
+
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