perf report: Display the branch counter histogram

Reusing the existing --total-cycles option to display the branch
counters. Add a new PERF_HPP_REPORT__BLOCK_BRANCH_COUNTER to display
the logged branch counter events. They are shown right after all the
cycle-related annotations.

Extend the 'struct block_info' to store and pass the branch counter
related information.

The annotation_br_cntr_entry() is to print the histogram of each branch
counter event. If the number of logged events is less than 4, the exact
number of the abbr name is printed. Otherwise, using '+' to stands for
more than 3 events.

Assume the number of logged events is less than 4.

The annotation_br_cntr_abbr_list() prints the branch counter's
abbreviation list. Press 'B' to display the list in the TUI mode.

  $ perf record -e "{branch-instructions:ppp,branch-misses}:S" -j any,counter
  $ perf report  --total-cycles --stdio

  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 1M of events 'anon group { branch-instructions:ppp, branch-misses }'
  # Event count (approx.): 1610046
  #
  # Branch counter abbr list:
  # branch-instructions:ppp = A
  # branch-misses = B
  # '-' No event occurs
  # '+' Event occurrences may be lost due to branch counter saturated
  #
  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  Branch Counter [Program Block Range]
  # ...............  ..............  ...........  ..........  ..............  ..................
  #
            57.55%            2.5M        0.00%           3     |A   |-   |                 ...
            25.27%            1.1M        0.00%           2     |AA  |-   |                 ...
            15.61%          667.2K        0.00%           1     |A   |-   |                 ...
             0.16%            6.9K        0.81%         575     |A   |-   |                 ...
             0.16%            6.8K        1.38%         977     |AA  |-   |                 ...
             0.16%            6.8K        0.04%          28     |AA  |B   |                 ...
             0.15%            6.6K        1.33%         946     |A   |-   |                 ...
             0.11%            4.5K        0.06%          46     |AAA+|-   |                 ...
             0.10%            4.4K        0.88%         624     |A   |-   |                 ...
             0.09%            3.7K        0.74%         524     |AAA+|B   |                 ...

With -v applied,

  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  Branch Counter [Program Block Range]
  # ...............  ..............  ...........  ..........  ..............  ..................
  #
            57.55%            2.5M        0.00%           3       A=1 ,B=-                  ...
            25.27%            1.1M        0.00%           2       A=2 ,B=-                  ...
            15.61%          667.2K        0.00%           1       A=1 ,B=-                  ...
             0.16%            6.9K        0.81%         575       A=1 ,B=-                  ...
             0.16%            6.8K        1.38%         977       A=2 ,B=-                  ...
             0.16%            6.8K        0.04%          28       A=2 ,B=1                  ...
             0.15%            6.6K        1.33%         946       A=1 ,B=-                  ...
             0.11%            4.5K        0.06%          46       A=3+,B=-                  ...
             0.10%            4.4K        0.88%         624       A=1 ,B=-                  ...
             0.09%            3.7K        0.74%         524       A=3+,B=1                  ...

Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240813160208.2493643-7-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 145 insertions, 0 deletions

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index c269758d47c8..5200cafe20e7 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -41,6 +41,7 @@
 #include "namespaces.h"
 #include "thread.h"
 #include "hashmap.h"
+#include "strbuf.h"
 #include <regex.h>
 #include <linux/bitops.h>
 #include <linux/kernel.h>
@@ -48,6 +49,7 @@
 #include <linux/zalloc.h>
 #include <subcmd/parse-options.h>
 #include <subcmd/run-command.h>
+#include <math.h>
 
 /* FIXME: For the HE_COLORSET */
 #include "ui/browser.h"
@@ -1719,6 +1721,149 @@ static void ipc_coverage_string(char *bf, int size, struct annotation *notes)
 		  ipc, coverage);
 }
 
+int annotation_br_cntr_abbr_list(char **str, struct evsel *evsel, bool header)
+{
+	struct evsel *pos;
+	struct strbuf sb;
+
+	if (evsel->evlist->nr_br_cntr <= 0)
+		return -ENOTSUP;
+
+	strbuf_init(&sb, /*hint=*/ 0);
+
+	if (header && strbuf_addf(&sb, "# Branch counter abbr list:\n"))
+		goto err;
+
+	evlist__for_each_entry(evsel->evlist, pos) {
+		if (!(pos->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_COUNTERS))
+			continue;
+		if (header && strbuf_addf(&sb, "#"))
+			goto err;
+
+		if (strbuf_addf(&sb, " %s = %s\n", pos->name, pos->abbr_name))
+			goto err;
+	}
+
+	if (header && strbuf_addf(&sb, "#"))
+		goto err;
+	if (strbuf_addf(&sb, " '-' No event occurs\n"))
+		goto err;
+
+	if (header && strbuf_addf(&sb, "#"))
+		goto err;
+	if (strbuf_addf(&sb, " '+' Event occurrences may be lost due to branch counter saturated\n"))
+		goto err;
+
+	*str = strbuf_detach(&sb, NULL);
+
+	return 0;
+err:
+	strbuf_release(&sb);
+	return -ENOMEM;
+}
+
+/* Assume the branch counter saturated at 3 */
+#define ANNOTATION_BR_CNTR_SATURATION		3
+
+int annotation_br_cntr_entry(char **str, int br_cntr_nr,
+			     u64 *br_cntr, int num_aggr,
+			     struct evsel *evsel)
+{
+	struct evsel *pos = evsel ? evlist__first(evsel->evlist) : NULL;
+	bool saturated = false;
+	int i, j, avg, used;
+	struct strbuf sb;
+
+	strbuf_init(&sb, /*hint=*/ 0);
+	for (i = 0; i < br_cntr_nr; i++) {
+		used = 0;
+		avg = ceil((double)(br_cntr[i] & ~ANNOTATION__BR_CNTR_SATURATED_FLAG) /
+			   (double)num_aggr);
+
+		/*
+		 * A histogram with the abbr name is displayed by default.
+		 * With -v, the exact number of branch counter is displayed.
+		 */
+		if (verbose) {
+			evlist__for_each_entry_from(evsel->evlist, pos) {
+				if ((pos->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_COUNTERS) &&
+				    (pos->br_cntr_idx == i))
+				break;
+			}
+			if (strbuf_addstr(&sb, pos->abbr_name))
+				goto err;
+
+			if (!br_cntr[i]) {
+				if (strbuf_addstr(&sb, "=-"))
+					goto err;
+			} else {
+				if (strbuf_addf(&sb, "=%d", avg))
+					goto err;
+			}
+			if (br_cntr[i] & ANNOTATION__BR_CNTR_SATURATED_FLAG) {
+				if (strbuf_addch(&sb, '+'))
+					goto err;
+			} else {
+				if (strbuf_addch(&sb, ' '))
+					goto err;
+			}
+
+			if ((i < br_cntr_nr - 1) && strbuf_addch(&sb, ','))
+				goto err;
+			continue;
+		}
+
+		if (strbuf_addch(&sb, '|'))
+			goto err;
+
+		if (!br_cntr[i]) {
+			if (strbuf_addch(&sb, '-'))
+				goto err;
+			used++;
+		} else {
+			evlist__for_each_entry_from(evsel->evlist, pos) {
+				if ((pos->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_COUNTERS) &&
+				    (pos->br_cntr_idx == i))
+					break;
+			}
+			if (br_cntr[i] & ANNOTATION__BR_CNTR_SATURATED_FLAG)
+				saturated = true;
+
+			for (j = 0; j < avg; j++, used++) {
+				/* Print + if the number of logged events > 3 */
+				if (j >= ANNOTATION_BR_CNTR_SATURATION) {
+					saturated = true;
+					break;
+				}
+				if (strbuf_addstr(&sb, pos->abbr_name))
+					goto err;
+			}
+
+			if (saturated) {
+				if (strbuf_addch(&sb, '+'))
+					goto err;
+				used++;
+			}
+			pos = list_next_entry(pos, core.node);
+		}
+
+		for (j = used; j < ANNOTATION_BR_CNTR_SATURATION + 1; j++) {
+			if (strbuf_addch(&sb, ' '))
+				goto err;
+		}
+	}
+
+	if (!verbose && strbuf_addch(&sb, br_cntr_nr ? '|' : ' '))
+		goto err;
+
+	*str = strbuf_detach(&sb, NULL);
+
+	return 0;
+err:
+	strbuf_release(&sb);
+	return -ENOMEM;
+}
+
 static void __annotation_line__write(struct annotation_line *al, struct annotation *notes,
 				     bool first_line, bool current_entry, bool change_color, int width,
 				     void *obj, unsigned int percent_type,