#include "config.h"
 #include "cache.h"
 #include "symbol.h"
+#include "units.h"
 #include "debug.h"
 #include "annotate.h"
 #include "evsel.h"
        return -1;
 }
 
+int __annotation__scnprintf_samples_period(struct annotation *notes,
+                                          char *bf, size_t size,
+                                          struct perf_evsel *evsel,
+                                          bool show_freq)
+{
+       const char *ev_name = perf_evsel__name(evsel);
+       char ref[30] = " show reference callgraph, ";
+       char sample_freq_str[64] = "";
+       unsigned long nr_samples = 0;
+       int nr_members = 1;
+       bool enable_ref = false;
+       u64 nr_events = 0;
+       char unit;
+       int i;
+
+       if (perf_evsel__is_group_event(evsel))
+                nr_members = evsel->nr_members;
+
+       for (i = 0; i < nr_members; i++) {
+               struct sym_hist *ah = annotation__histogram(notes, evsel->idx + i);
+
+               nr_samples += ah->nr_samples;
+               nr_events  += ah->period;
+       }
+
+       if (symbol_conf.show_ref_callgraph && strstr(ev_name, "call-graph=no"))
+               enable_ref = true;
+
+       if (show_freq)
+               scnprintf(sample_freq_str, sizeof(sample_freq_str), " %d Hz,", evsel->attr.sample_freq);
+
+       nr_samples = convert_unit(nr_samples, &unit);
+       return scnprintf(bf, size, "Samples: %lu%c of event%s '%s',%s%sEvent count (approx.): %" PRIu64,
+                        nr_samples, unit, evsel->nr_members > 1 ? "s" : "",
+                        ev_name, sample_freq_str, enable_ref ? ref : " ", nr_events);
+}
+
 #define ANNOTATION__CFG(n) \
        { .name = #n, .value = &annotation__default_options.n, }
 
 
 void annotation_line__write(struct annotation_line *al, struct annotation *notes,
                            struct annotation_write_ops *ops);
 
+int __annotation__scnprintf_samples_period(struct annotation *notes,
+                                          char *bf, size_t size,
+                                          struct perf_evsel *evsel,
+                                          bool show_freq);
+
+static inline int annotation__scnprintf_samples_period(struct annotation *notes,
+                                                      char *bf, size_t size,
+                                                      struct perf_evsel *evsel)
+{
+       return __annotation__scnprintf_samples_period(notes, bf, size, evsel, true);
+}
+
 int disasm_line__scnprintf(struct disasm_line *dl, char *bf, size_t size, bool raw);
 size_t disasm__fprintf(struct list_head *head, FILE *fp);
 void symbol__calc_percent(struct symbol *sym, struct perf_evsel *evsel);