[PATCH] perf env: Find correct branch counter info on hybrid

[kan . liang]

From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>

No event is printed in the "Branch Counter" column on hybrid machines.

For example,
 $perf record -e "{cpu_core/branch-instructions/pp,cpu_core/branches/}:S"
 -j any,counter
 $perf report --total-cycles

 # Branch counter abbr list:
 # cpu_core/branch-instructions/pp = A
 # cpu_core/branches/ = B
 # '-' No event occurs
 # '+' Event occurrences may be lost due to branch counter saturated
 #
 # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  Branch Counter
 # ...............  ..............  ...........  ..........  ..............
           44.54%          727.1K        0.00%           1   |+   |+   |
           36.31%          592.7K        0.00%           2   |+   |+   |
           17.83%          291.1K        0.00%           1   |+   |+   |

The branch counter information (br_cntr_width and br_cntr_nr) in the
perf_env is retrieved from the CPU_PMU_CAPS. However, the CPU_PMU_CAPS
is not available on hybrid machines. Without the width information, the
number of occurrences of an event cannot be calculated.

For a hybrid machine, the caps information should be retrieved from the
PMU_CAPS, and stored in the perf_env->pmu_caps.

Add a perf_env__find_br_cntr_info() to return the correct branch counter
information from the corresponding fields.

Fixes: 6f9d8d1de2c6 ("perf script: Add branch counters")
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---
 tools/perf/builtin-script.c |  5 +++--
 tools/perf/util/annotate.c  |  5 +++--
 tools/perf/util/env.c       | 15 +++++++++++++++
 tools/perf/util/env.h       |  3 +++
 tools/perf/util/session.c   |  6 ++++--
 5 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index dbe792b52c5c..a644787fa9e1 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1241,10 +1241,11 @@ static int ip__fprintf_jump(uint64_t ip, struct branch_entry *en,
 	}
 
 	if (PRINT_FIELD(BRCNTR)) {
-		unsigned int width = evsel__env(evsel)->br_cntr_width;
-		unsigned int i = 0, j, num, mask = (1L << width) - 1;
 		struct evsel *pos = evsel__leader(evsel);
+		unsigned int i = 0, j, num, mask, width;
 
+		perf_env__find_br_cntr_info(evsel__env(evsel), NULL, &width);
+		mask = (1L << width) - 1;
 		printed += fprintf(fp, "br_cntr: ");
 		evlist__for_each_entry_from(evsel->evlist, pos) {
 			if (!(pos->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_COUNTERS))
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 4990c70b1794..c6ebde9d40a8 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -333,14 +333,15 @@ static int symbol__account_br_cntr(struct annotated_branch *branch,
 {
 	unsigned int br_cntr_nr = evsel__leader(evsel)->br_cntr_nr;
 	unsigned int base = evsel__leader(evsel)->br_cntr_idx;
-	unsigned int width = evsel__env(evsel)->br_cntr_width;
 	unsigned int off = offset * evsel->evlist->nr_br_cntr;
-	unsigned int i, mask = (1L << width) - 1;
 	u64 *branch_br_cntr = branch->br_cntr;
+	unsigned int i, mask, width;
 
 	if (!br_cntr || !branch_br_cntr)
 		return 0;
 
+	perf_env__find_br_cntr_info(evsel__env(evsel), NULL, &width);
+	mask = (1L << width) - 1;
 	for (i = 0; i < br_cntr_nr; i++) {
 		u64 cntr = (br_cntr >> i * width) & mask;
 
diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index a459374d0a1a..1edbccfc3281 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -624,3 +624,18 @@ char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
 	free(cap_eq);
 	return NULL;
 }
+
+void perf_env__find_br_cntr_info(struct perf_env *env,
+				 unsigned int *nr,
+				 unsigned int *width)
+{
+	if (nr) {
+		*nr = env->cpu_pmu_caps ? env->br_cntr_nr :
+					  env->pmu_caps->br_cntr_nr;
+	}
+
+	if (width) {
+		*width = env->cpu_pmu_caps ? env->br_cntr_width :
+					     env->pmu_caps->br_cntr_width;
+	}
+}
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 2a2c37cc40b7..51b36c36019b 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -192,4 +192,7 @@ char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
 			     const char *cap);
 
 bool perf_env__has_pmu_mapping(struct perf_env *env, const char *pmu_name);
+void perf_env__find_br_cntr_info(struct perf_env *env,
+				 unsigned int *nr,
+				 unsigned int *width);
 #endif /* __PERF_ENV_H */
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index b492300ec959..dbaf07bf6c5f 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -856,7 +856,6 @@ static void branch_stack__printf(struct perf_sample *sample,
 	struct branch_entry *entries = perf_sample__branch_entries(sample);
 	bool callstack = evsel__has_branch_callstack(evsel);
 	u64 *branch_stack_cntr = sample->branch_stack_cntr;
-	struct perf_env *env = evsel__env(evsel);
 	uint64_t i;
 
 	if (!callstack) {
@@ -900,8 +899,11 @@ static void branch_stack__printf(struct perf_sample *sample,
 	}
 
 	if (branch_stack_cntr) {
+		unsigned int br_cntr_width, br_cntr_nr;
+
+		perf_env__find_br_cntr_info(evsel__env(evsel), &br_cntr_nr, &br_cntr_width);
 		printf("... branch stack counters: nr:%" PRIu64 " (counter width: %u max counter nr:%u)\n",
-			sample->branch_stack->nr, env->br_cntr_width, env->br_cntr_nr);
+			sample->branch_stack->nr, br_cntr_width, br_cntr_nr);
 		for (i = 0; i < sample->branch_stack->nr; i++)
 			printf("..... %2"PRIu64": %016" PRIx64 "\n", i, branch_stack_cntr[i]);
 	}
-- 
2.38.1