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authorArnaldo Carvalho de Melo <acme@redhat.com>2018-05-25 11:27:38 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-06-04 10:28:52 -0300
commit9132d3d92d8953ee79690408a9a24d938be22cd8 (patch)
tree385f92a51cfd839aeaeb04e3c2ce15b4b6de017e /tools
parent9fd5578a3cdd6cb59603b04a9282199d08f85607 (diff)
perf annotate: Add comment about annotated_src->nr_histograms
When we have multiple groups in an evlist, say: $ perf stat -e '{cycles,instructions},{cache-references,cache-misses}' sleep 1 Performance counter stats for 'sleep 1': 343,134 cycles:u 249,292 instructions:u # 0.73 insn per cycle 15,556 cache-references:u 8,925 cache-misses:u # 57.373 % of all cache refs 1.000957550 seconds time elapsed $ Then the perf_evsel instances for the two group leaders ("cycles" and "cache-references") will have evsel->nr_members set to 2, while all the evsel->evlist->nr_entries will be set to 4, so we can't use evsel->evlist->nr_entries everywhere, as event groups need to be taken into account. But this probably requires us to audit at least the forced-group code, where we want all of the events to be in a "group", to see them all in the screen, one column for each, even knowing that they were not necessarily scheduled to count at the same time by the kernel perf subsystem. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-2g0vwqnc49wl4ttjk8dvpgcc@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/annotate.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 7ad503fbff74..3dc4ca1d6c08 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -202,6 +202,10 @@ struct cyc_hist {
/** struct annotated_source - symbols with hits have this attached as in sannotation
*
* @histograms: Array of addr hit histograms per event being monitored
+ * nr_histograms: This may not be the same as evsel->evlist->nr_entries if
+ * we have more than a group in a evlist, where we will want
+ * to see each group separately, that is why symbol__annotate2()
+ * sets src->nr_histograms to evsel->nr_members.
* @lines: If 'print_lines' is specified, per source code line percentages
* @source: source parsed from a disassembler like objdump -dS
* @cyc_hist: Average cycles per basic block