perf annotate: Record the min/max cycles

Currently perf has a feature to account cycles for LBRs

For example, on skylake:

  perf record -b ...
  perf report or perf annotate

And then browsing the annotate browser gives average cycle counts for
program blocks.

For some analysis it would be useful if we could know not only the
average cycles but also the min and max cycles.

This patch records the min and max cycles.

Signed-off-by: Jin Yao <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Switch from max/min to min/max ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: Jin Yao

tools/perf/util/annotate.c

@@ -760,6 +760,15 @@ static int __symbol__account_cycles(struct annotation *notes,
 	ch[offset].num_aggr++;
 	ch[offset].cycles_aggr += cycles;
 
+	if (cycles > ch[offset].cycles_max)
+		ch[offset].cycles_max = cycles;
+
+	if (ch[offset].cycles_min) {
+		if (cycles && cycles < ch[offset].cycles_min)
+			ch[offset].cycles_min = cycles;
+	} else
+		ch[offset].cycles_min = cycles;
+
 	if (!have_start && ch[offset].have_start)
 		return 0;
 	if (ch[offset].num) {
@@ -953,8 +962,11 @@ void annotation__compute_ipc(struct annotation *notes, size_t size)
 			if (ch->have_start)
 				annotation__count_and_fill(notes, ch->start, offset, ch);
 			al = notes->offsets[offset];
-			if (al && ch->num_aggr)
+			if (al && ch->num_aggr) {
 				al->cycles = ch->cycles_aggr / ch->num_aggr;
+				al->cycles_max = ch->cycles_max;
+				al->cycles_min = ch->cycles_min;
+			}
 			notes->have_cycles = true;
 		}
 	}

tools/perf/util/annotate.h

@@ -105,6 +105,8 @@ struct annotation_line {
 	int			 jump_sources;
 	float			 ipc;
 	u64			 cycles;
+	u64			 cycles_max;
+	u64			 cycles_min;
 	size_t			 privsize;
 	char			*path;
 	u32			 idx;
@@ -186,6 +188,8 @@ struct cyc_hist {
 	u64	start;
 	u64	cycles;
 	u64	cycles_aggr;
+	u64	cycles_max;
+	u64	cycles_min;
 	u32	num;
 	u32	num_aggr;
 	u8	have_start;