perf header: Store PMU caps in an array of strings

Currently all capabilities are stored in a single string separated by
NULL character. Instead, store them in an array which makes searching of
capability easier.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ananth Narayan <ananth.narayan@amd.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rrichter@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Santosh Shukla <santosh.shukla@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: like.xu.linux@gmail.com
Cc: x86@kernel.org
Link: https://lore.kernel.org/r/20220604044519.594-5-ravi.bangoria@amd.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/env.c

@@ -179,7 +179,7 @@ static void perf_env__purge_bpf(struct perf_env *env __maybe_unused)
 
 void perf_env__exit(struct perf_env *env)
 {
-	int i;
+	int i, j;
 
 	perf_env__purge_bpf(env);
 	perf_env__purge_cgroups(env);
@@ -196,6 +196,8 @@ void perf_env__exit(struct perf_env *env)
 	zfree(&env->sibling_threads);
 	zfree(&env->pmu_mappings);
 	zfree(&env->cpu);
+	for (i = 0; i < env->nr_cpu_pmu_caps; i++)
+		zfree(&env->cpu_pmu_caps[i]);
 	zfree(&env->cpu_pmu_caps);
 	zfree(&env->numa_map);
 
@@ -218,6 +220,8 @@ void perf_env__exit(struct perf_env *env)
 	zfree(&env->hybrid_nodes);
 
 	for (i = 0; i < env->nr_hybrid_cpc_nodes; i++) {
+		for (j = 0; j < env->hybrid_cpc_nodes[i].nr_cpu_pmu_caps; j++)
+			zfree(&env->hybrid_cpc_nodes[i].cpu_pmu_caps[j]);
 		zfree(&env->hybrid_cpc_nodes[i].cpu_pmu_caps);
 		zfree(&env->hybrid_cpc_nodes[i].pmu_name);
 	}

tools/perf/util/env.h

@@ -46,7 +46,7 @@ struct hybrid_node {
 struct hybrid_cpc_node {
 	int		nr_cpu_pmu_caps;
 	unsigned int    max_branches;
-	char            *cpu_pmu_caps;
+	char            **cpu_pmu_caps;
 	char            *pmu_name;
 };
 
@@ -81,7 +81,7 @@ struct perf_env {
 	char			*sibling_dies;
 	char			*sibling_threads;
 	char			*pmu_mappings;
-	char			*cpu_pmu_caps;
+	char			**cpu_pmu_caps;
 	struct cpu_topology_map	*cpu;
 	struct cpu_cache_level	*caches;
 	int			 caches_cnt;

tools/perf/util/header.c

@@ -2051,26 +2051,21 @@ static void print_compressed(struct feat_fd *ff, FILE *fp)
 		ff->ph->env.comp_level, ff->ph->env.comp_ratio);
 }
 
-static void print_per_cpu_pmu_caps(FILE *fp, int nr_caps, char *cpu_pmu_caps,
+static void print_per_cpu_pmu_caps(FILE *fp, int nr_caps, char **cpu_pmu_caps,
 				   char *pmu_name)
 {
-	const char *delimiter;
-	char *str, buf[128];
+	const char *delimiter = "";
+	int i;
 
 	if (!nr_caps) {
 		fprintf(fp, "# %s pmu capabilities: not available\n", pmu_name);
 		return;
 	}
 
-	scnprintf(buf, sizeof(buf), "# %s pmu capabilities: ", pmu_name);
-
-	delimiter = buf;
-
-	str = cpu_pmu_caps;
-	while (nr_caps--) {
-		fprintf(fp, "%s%s", delimiter, str);
+	fprintf(fp, "# %s pmu capabilities: ", pmu_name);
+	for (i = 0; i < nr_caps; i++) {
+		fprintf(fp, "%s%s", delimiter, cpu_pmu_caps[i]);
 		delimiter = ", ";
-		str += strlen(str) + 1;
 	}
 
 	fprintf(fp, "\n");
@@ -3202,27 +3197,26 @@ static int process_compressed(struct feat_fd *ff,
 }
 
 static int process_per_cpu_pmu_caps(struct feat_fd *ff, int *nr_cpu_pmu_caps,
-				    char **cpu_pmu_caps,
+				    char ***cpu_pmu_caps,
 				    unsigned int *max_branches)
 {
-	char *name, *value;
-	struct strbuf sb;
-	u32 nr_caps;
+	char *name, *value, *ptr;
+	u32 nr_caps, i;
+
+	*nr_cpu_pmu_caps = 0;
+	*cpu_pmu_caps = NULL;
 
 	if (do_read_u32(ff, &nr_caps))
 		return -1;
 
-	if (!nr_caps) {
-		pr_debug("cpu pmu capabilities not available\n");
+	if (!nr_caps)
 		return 0;
-	}
 
-	*nr_cpu_pmu_caps = nr_caps;
-
-	if (strbuf_init(&sb, 128) < 0)
+	*cpu_pmu_caps = zalloc(sizeof(char *) * nr_caps);
+	if (!*cpu_pmu_caps)
 		return -1;
 
-	while (nr_caps--) {
+	for (i = 0; i < nr_caps; i++) {
 		name = do_read_string(ff);
 		if (!name)
 			goto error;
@@ -3231,12 +3225,10 @@ static int process_per_cpu_pmu_caps(struct feat_fd *ff, int *nr_cpu_pmu_caps,
 		if (!value)
 			goto free_name;
 
-		if (strbuf_addf(&sb, "%s=%s", name, value) < 0)
+		if (asprintf(&ptr, "%s=%s", name, value) < 0)
 			goto free_value;
 
-		/* include a NULL character at the end */
-		if (strbuf_add(&sb, "", 1) < 0)
-			goto free_value;
+		(*cpu_pmu_caps)[i] = ptr;
 
 		if (!strcmp(name, "branches"))
 			*max_branches = atoi(value);
@@ -3244,7 +3236,7 @@ static int process_per_cpu_pmu_caps(struct feat_fd *ff, int *nr_cpu_pmu_caps,
 		free(value);
 		free(name);
 	}
-	*cpu_pmu_caps = strbuf_detach(&sb, NULL);
+	*nr_cpu_pmu_caps = nr_caps;
 	return 0;
 
 free_value:
@@ -3252,16 +3244,24 @@ free_value:
 free_name:
 	free(name);
 error:
-	strbuf_release(&sb);
+	for (; i > 0; i--)
+		free((*cpu_pmu_caps)[i - 1]);
+	free(*cpu_pmu_caps);
+	*cpu_pmu_caps = NULL;
+	*nr_cpu_pmu_caps = 0;
 	return -1;
 }
 
 static int process_cpu_pmu_caps(struct feat_fd *ff,
 				void *data __maybe_unused)
 {
-	return process_per_cpu_pmu_caps(ff, &ff->ph->env.nr_cpu_pmu_caps,
+	int ret = process_per_cpu_pmu_caps(ff, &ff->ph->env.nr_cpu_pmu_caps,
 					&ff->ph->env.cpu_pmu_caps,
 					&ff->ph->env.max_branches);
+
+	if (!ret && !ff->ph->env.cpu_pmu_caps)
+		pr_debug("cpu pmu capabilities not available\n");
+	return ret;
 }
 
 static int process_hybrid_cpu_pmu_caps(struct feat_fd *ff,
@@ -3270,6 +3270,7 @@ static int process_hybrid_cpu_pmu_caps(struct feat_fd *ff,
 	struct hybrid_cpc_node *nodes;
 	u32 nr_pmu, i;
 	int ret;
+	int j;
 
 	if (do_read_u32(ff, &nr_pmu))
 		return -1;
@@ -3297,6 +3298,8 @@ static int process_hybrid_cpu_pmu_caps(struct feat_fd *ff,
 			ret = -1;
 			goto err;
 		}
+		if (!n->nr_cpu_pmu_caps)
+			pr_debug("%s pmu capabilities not available\n", n->pmu_name);
 	}
 
 	ff->ph->env.nr_hybrid_cpc_nodes = nr_pmu;
@@ -3305,6 +3308,8 @@ static int process_hybrid_cpu_pmu_caps(struct feat_fd *ff,
 
 err:
 	for (i = 0; i < nr_pmu; i++) {
+		for (j = 0; j < nodes[i].nr_cpu_pmu_caps; j++)
+			free(nodes[i].cpu_pmu_caps[j]);
 		free(nodes[i].cpu_pmu_caps);
 		free(nodes[i].pmu_name);
 	}