[PATCH v1 2/2] perf header: Support hybrid CPU_PMU_CAPS

[Jin Yao]

On hybrid platform, it may have several cpu pmus, such as,
"cpu_core" and "cpu_atom". The CPU_PMU_CAPS feature in perf
header needs to be improved to support multiple cpu pmus.

The new layout in header is defined as:

<nr_caps>
<caps string>
<caps string>
<pmu name>
<nr of rest pmus>

It's considered to be compatible with old perf.data (the
perf.data generated by old perf tool).

With this patch, some examples,

New perf tool with new perf.data
(new perf.data is generated on hybrid platform):

  root@otcpl-adl-s-2:~# perf report --header-only -I
  ...
  # cpu_core pmu capabilities: branches=32, max_precise=3, pmu_name=alderlake_hybrid
  # cpu_atom pmu capabilities: branches=32, max_precise=3, pmu_name=alderlake_hybrid

New perf tool with new perf.data
(new perf.data is generated on non-hybrid platform):

  root@kbl-ppc:~# perf report --header-only -I
  ...
  # cpu pmu capabilities: branches=32, max_precise=3, pmu_name=skylake

New perf tool with old perf.data
(old perf.data is generated by old perf tool on non-hybrid platform):

  root@kbl-ppc:~# perf report --header-only -I
  ...
  # cpu pmu capabilities: branches=32, max_precise=3, pmu_name=skylake

Note that: this patch is on tmp.perf/core.

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
---
 tools/perf/util/env.c    |   6 ++
 tools/perf/util/env.h    |  11 ++-
 tools/perf/util/header.c | 175 ++++++++++++++++++++++++++++++++++-----
 3 files changed, 168 insertions(+), 24 deletions(-)

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 9e05eca324a1..8ef24aad2152 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -208,6 +208,12 @@ void perf_env__exit(struct perf_env *env)
 		zfree(&env->hybrid_nodes[i].pmu_name);
 	}
 	zfree(&env->hybrid_nodes);
+
+	for (i = 0; i < env->nr_cpu_pmu_caps_nodes; i++) {
+		zfree(&env->cpu_pmu_caps_nodes[i].cpu_pmu_caps);
+		zfree(&env->cpu_pmu_caps_nodes[i].pmu_name);
+	}
+	zfree(&env->cpu_pmu_caps_nodes);
 }
 
 void perf_env__init(struct perf_env *env __maybe_unused)
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 9ca7633787e1..5552c98a6a76 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -42,6 +42,13 @@ struct hybrid_node {
 	struct perf_cpu_map	*map;
 };
 
+struct cpu_pmu_caps_node {
+	int		nr_cpu_pmu_caps;
+	unsigned int	max_branches;
+	char		*cpu_pmu_caps;
+	char		*pmu_name;
+};
+
 struct perf_env {
 	char			*hostname;
 	char			*os_release;
@@ -63,15 +70,14 @@ struct perf_env {
 	int			nr_memory_nodes;
 	int			nr_pmu_mappings;
 	int			nr_groups;
-	int			nr_cpu_pmu_caps;
 	int			nr_hybrid_nodes;
+	int			nr_cpu_pmu_caps_nodes;
 	char			*cmdline;
 	const char		**cmdline_argv;
 	char			*sibling_cores;
 	char			*sibling_dies;
 	char			*sibling_threads;
 	char			*pmu_mappings;
-	char			*cpu_pmu_caps;
 	struct cpu_topology_map	*cpu;
 	struct cpu_cache_level	*caches;
 	int			 caches_cnt;
@@ -84,6 +90,7 @@ struct perf_env {
 	struct memory_node	*memory_nodes;
 	unsigned long long	 memory_bsize;
 	struct hybrid_node	*hybrid_nodes;
+	struct cpu_pmu_caps_node	*cpu_pmu_caps_nodes;
 #ifdef HAVE_LIBBPF_SUPPORT
 	/*
 	 * bpf_info_lock protects bpf rbtrees. This is needed because the
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index dff89c0be79c..6989c57b57e6 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -49,6 +49,7 @@
 #include "cputopo.h"
 #include "bpf-event.h"
 #include "clockid.h"
+#include "pmu-hybrid.h"
 
 #include <linux/ctype.h>
 #include <internal/lib.h>
@@ -1459,18 +1460,22 @@ static int write_compressed(struct feat_fd *ff __maybe_unused,
 	return do_write(ff, &(ff->ph->env.comp_mmap_len), sizeof(ff->ph->env.comp_mmap_len));
 }
 
-static int write_cpu_pmu_caps(struct feat_fd *ff,
-			      struct evlist *evlist __maybe_unused)
+static int write_per_cpu_pmu_caps(struct feat_fd *ff, struct perf_pmu *pmu,
+				  int nr)
 {
-	struct perf_pmu *cpu_pmu = perf_pmu__find("cpu");
 	struct perf_pmu_caps *caps = NULL;
 	int nr_caps;
 	int ret;
 
-	if (!cpu_pmu)
-		return -ENOENT;
-
-	nr_caps = perf_pmu__caps_parse(cpu_pmu);
+	/*
+	 * The layout is:
+	 * <nr_caps>
+	 * <caps string>
+	 * <caps string>
+	 * <pmu name>
+	 * <nr of rest pmus>
+	 */
+	nr_caps = perf_pmu__caps_parse(pmu);
 	if (nr_caps < 0)
 		return nr_caps;
 
@@ -1478,7 +1483,7 @@ static int write_cpu_pmu_caps(struct feat_fd *ff,
 	if (ret < 0)
 		return ret;
 
-	list_for_each_entry(caps, &cpu_pmu->caps, list) {
+	list_for_each_entry(caps, &pmu->caps, list) {
 		ret = do_write_string(ff, caps->name);
 		if (ret < 0)
 			return ret;
@@ -1488,9 +1493,49 @@ static int write_cpu_pmu_caps(struct feat_fd *ff,
 			return ret;
 	}
 
+	ret = do_write_string(ff, pmu->name);
+	if (ret < 0)
+		return ret;
+
+	ret = do_write(ff, &nr, sizeof(nr));
+	if (ret < 0)
+		return ret;
+
 	return ret;
 }
 
+static int write_cpu_pmu_caps(struct feat_fd *ff,
+			      struct evlist *evlist __maybe_unused)
+{
+	struct perf_pmu *pmu = perf_pmu__find("cpu");
+	u32 nr;
+	int ret;
+
+	if (pmu)
+		nr = 1;
+	else {
+		nr = perf_pmu__hybrid_pmu_num();
+		pmu = NULL;
+	}
+
+	if (nr == 0)
+		return -1;
+
+	if (pmu) {
+		ret = write_per_cpu_pmu_caps(ff, pmu, 0);
+		if (ret < 0)
+			return ret;
+	} else {
+		perf_pmu__for_each_hybrid_pmu(pmu) {
+			ret = write_per_cpu_pmu_caps(ff, pmu, --nr);
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
 static void print_hostname(struct feat_fd *ff, FILE *fp)
 {
 	fprintf(fp, "# hostname : %s\n", ff->ph->env.hostname);
@@ -1963,18 +2008,28 @@ static void print_compressed(struct feat_fd *ff, FILE *fp)
 		ff->ph->env.comp_level, ff->ph->env.comp_ratio);
 }
 
-static void print_cpu_pmu_caps(struct feat_fd *ff, FILE *fp)
+static void print_per_cpu_pmu_caps(FILE *fp, struct cpu_pmu_caps_node *n)
 {
-	const char *delimiter = "# cpu pmu capabilities: ";
-	u32 nr_caps = ff->ph->env.nr_cpu_pmu_caps;
-	char *str;
+	const char *delimiter;
+	u32 nr_caps = n->nr_cpu_pmu_caps;
+	char *str, buf[128];
 
 	if (!nr_caps) {
-		fprintf(fp, "# cpu pmu capabilities: not available\n");
+		if (!n->pmu_name)
+			fprintf(fp, "# cpu pmu capabilities: not available\n");
+		else
+			fprintf(fp, "# %s pmu capabilities: not available\n", n->pmu_name);
 		return;
 	}
 
-	str = ff->ph->env.cpu_pmu_caps;
+	if (!n->pmu_name)
+		scnprintf(buf, sizeof(buf), "# cpu pmu capabilities: ");
+	else
+		scnprintf(buf, sizeof(buf), "# %s pmu capabilities: ", n->pmu_name);
+
+	delimiter = buf;
+
+	str = n->cpu_pmu_caps;
 	while (nr_caps--) {
 		fprintf(fp, "%s%s", delimiter, str);
 		delimiter = ", ";
@@ -1984,6 +2039,17 @@ static void print_cpu_pmu_caps(struct feat_fd *ff, FILE *fp)
 	fprintf(fp, "\n");
 }
 
+static void print_cpu_pmu_caps(struct feat_fd *ff, FILE *fp)
+{
+	struct cpu_pmu_caps_node *n;
+	int i;
+
+	for (i = 0; i < ff->ph->env.nr_cpu_pmu_caps_nodes; i++) {
+		n = &ff->ph->env.cpu_pmu_caps_nodes[i];
+		print_per_cpu_pmu_caps(fp, n);
+	}
+}
+
 static void print_pmu_mappings(struct feat_fd *ff, FILE *fp)
 {
 	const char *delimiter = "# pmu mappings: ";
@@ -3093,13 +3159,14 @@ static int process_compressed(struct feat_fd *ff,
 	return 0;
 }
 
-static int process_cpu_pmu_caps(struct feat_fd *ff,
-				void *data __maybe_unused)
+static int process_cpu_pmu_caps_node(struct feat_fd *ff,
+				     struct cpu_pmu_caps_node *n, bool *end)
 {
-	char *name, *value;
+	char *name, *value, *pmu_name;
 	struct strbuf sb;
-	u32 nr_caps;
+	u32 nr_caps, nr;
 
+	*end = false;
 	if (do_read_u32(ff, &nr_caps))
 		return -1;
 
@@ -3108,7 +3175,7 @@ static int process_cpu_pmu_caps(struct feat_fd *ff,
 		return 0;
 	}
 
-	ff->ph->env.nr_cpu_pmu_caps = nr_caps;
+	n->nr_cpu_pmu_caps = nr_caps;
 
 	if (strbuf_init(&sb, 128) < 0)
 		return -1;
@@ -3129,13 +3196,33 @@ static int process_cpu_pmu_caps(struct feat_fd *ff,
 		if (strbuf_add(&sb, "", 1) < 0)
 			goto free_value;
 
-		if (!strcmp(name, "branches"))
-			ff->ph->env.max_branches = atoi(value);
+		if (!strcmp(name, "branches")) {
+			n->max_branches = atoi(value);
+			if (n->max_branches > ff->ph->env.max_branches)
+				ff->ph->env.max_branches = n->max_branches;
+		}
 
 		free(value);
 		free(name);
 	}
-	ff->ph->env.cpu_pmu_caps = strbuf_detach(&sb, NULL);
+
+	/*
+	 * Old perf.data may not have pmu_name,
+	 */
+	pmu_name = do_read_string(ff);
+	if (!pmu_name || strncmp(pmu_name, "cpu_", 4)) {
+		*end = true;
+		goto out;
+	}
+
+	if (do_read_u32(ff, &nr))
+		return -1;
+
+	if (nr == 0)
+		*end = true;
+out:
+	n->cpu_pmu_caps = strbuf_detach(&sb, NULL);
+	n->pmu_name = pmu_name;
 	return 0;
 
 free_value:
@@ -3147,6 +3234,50 @@ static int process_cpu_pmu_caps(struct feat_fd *ff,
 	return -1;
 }
 
+static int process_cpu_pmu_caps(struct feat_fd *ff,
+				void *data __maybe_unused)
+{
+	struct cpu_pmu_caps_node *nodes = NULL, *tmp;
+	int ret, i, nr_alloc = 1, nr_used = 0;
+	bool end;
+
+	while (1) {
+		if (nr_used == nr_alloc || !nodes) {
+			nr_alloc *= 2;
+			tmp = realloc(nodes, sizeof(*nodes) * nr_alloc);
+			if (!tmp)
+				return -ENOMEM;
+			memset(tmp + nr_used, 0,
+			       sizeof(*nodes) * (nr_alloc - nr_used));
+			nodes = tmp;
+		}
+
+		ret = process_cpu_pmu_caps_node(ff, &nodes[nr_used], &end);
+		if (ret) {
+			if (nr_used)
+				break;
+			goto err;
+		}
+
+		nr_used++;
+		if (end)
+			break;
+	}
+
+	ff->ph->env.nr_cpu_pmu_caps_nodes = (u32)nr_used;
+	ff->ph->env.cpu_pmu_caps_nodes = nodes;
+	return 0;
+
+err:
+	for (i = 0; i < nr_used; i++) {
+		free(nodes[i].cpu_pmu_caps);
+		free(nodes[i].pmu_name);
+	}
+
+	free(nodes);
+	return ret;
+}
+
 #define FEAT_OPR(n, func, __full_only) \
 	[HEADER_##n] = {					\
 		.name	    = __stringify(n),			\
-- 
2.17.1