perf annotate: Display total number of samples with --show-total-period

To compare two records on an instruction base, with --show-total-period
option provided, display total number of samples that belong to a line
in assembly language.

New hot key 't' is introduced for 'perf annotate' TUI.

Signed-off-by: Martin Liska <mliska@suse.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/5583E26D.1040407@suse.cz
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index cadbdc9..c8c18ca 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -72,7 +72,7 @@
 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);
 double disasm__calc_percent(struct annotation *notes, int evidx, s64 offset,
-			    s64 end, const char **path);
+			    s64 end, const char **path, u64 *nr_samples);
 
 struct sym_hist {
 	u64		sum;
@@ -82,6 +82,7 @@
 struct source_line_percent {
 	double		percent;
 	double		percent_sum;
+	double          samples;
 };
 
 struct source_line {