[PATCH v8 perf,bpf 09/15] perf, bpf: save btf information as headers to perf.data

Song Liu
2019-03-11T20:08:05Z

This patch enables perf-record to save btf information as headers to
perf.data A new header type HEADER_BPF_BTF is introduced for this data.

Signed-off-by: Song Liu <songliubraving@fb.com>
---
tools/perf/util/header.c | 101 ++++++++++++++++++++++++++++++++++++++-
tools/perf/util/header.h | 1 +
2 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index e53ee3111430..e5a86b9f68db 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1118,6 +1118,39 @@ static int write_bpf_prog_info(struct feat_fd *ff,
return ret;
}

+static int write_bpf_btf(struct feat_fd *ff,
+ struct perf_evlist *evlist __maybe_unused)
+{
+ struct perf_env *env = &ff->ph->env;
+ struct rb_root *root;
+ struct rb_node *next;
+ int ret;
+
+ down_read(&env->bpf_progs.lock);
+
+ ret = do_write(ff, &env->bpf_progs.btfs_cnt,
+ sizeof(env->bpf_progs.btfs_cnt));
+
+ if (ret < 0)
+ goto out;
+
+ root = &env->bpf_progs.btfs;
+ next = rb_first(root);
+ while (next) {
+ struct btf_node *node;
+
+ node = rb_entry(next, struct btf_node, rb_node);
+ next = rb_next(&node->rb_node);
+ ret = do_write(ff, &node->id,
+ sizeof(u32) * 2 + node->data_size);
+ if (ret < 0)
+ goto out;
+ }
+out:
+ up_read(&env->bpf_progs.lock);
+ return ret;
+}
+
static int cpu_cache_level__sort(const void *a, const void *b)
{
struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
@@ -1621,6 +1654,28 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
up_read(&env->bpf_progs.lock);
}

+static void print_bpf_btf(struct feat_fd *ff, FILE *fp)
+{
+ struct perf_env *env = &ff->ph->env;
+ struct rb_root *root;
+ struct rb_node *next;
+
+ down_read(&env->bpf_progs.lock);
+
+ root = &env->bpf_progs.btfs;
+ next = rb_first(root);
+
+ while (next) {
+ struct btf_node *node;
+
+ node = rb_entry(next, struct btf_node, rb_node);
+ next = rb_next(&node->rb_node);
+ fprintf(fp, "# btf info of id %u\n", node->id);
+ }
+
+ up_read(&env->bpf_progs.lock);
+}
+
static void free_event_desc(struct perf_evsel *events)
{
struct perf_evsel *evsel;
@@ -2722,6 +2777,49 @@ static int process_bpf_prog_info(struct feat_fd *ff,
return err;
}

+static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
+{
+ struct perf_env *env = &ff->ph->env;
+ u32 count, i;
+
+ if (ff->ph->needs_swap) {
+ pr_warning("interpreting btf from systems with endianity is not yet supported\n");
+ return 0;
+ }
+
+ if (do_read_u32(ff, &count))
+ return -1;
+
+ down_write(&env->bpf_progs.lock);
+
+ for (i = 0; i < count; ++i) {
+ struct btf_node *node;
+ u32 id, data_size;
+
+ if (do_read_u32(ff, &id))
+ return -1;
+ if (do_read_u32(ff, &data_size))
+ return -1;
+
+ node = malloc(sizeof(struct btf_node) + data_size);
+ if (!node)
+ return -1;
+
+ node->id = id;
+ node->data_size = data_size;
+
+ if (__do_read(ff, node->data, data_size)) {
+ free(node);
+ return -1;
+ }
+
+ perf_env__insert_btf(env, node);
+ }
+
+ up_write(&env->bpf_progs.lock);
+ return 0;
+}
+
struct feature_ops {
int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
void (*print)(struct feat_fd *ff, FILE *fp);
@@ -2782,7 +2880,8 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
FEAT_OPR(SAMPLE_TIME, sample_time, false),
FEAT_OPR(MEM_TOPOLOGY, mem_topology, true),
FEAT_OPR(CLOCKID, clockid, false),
- FEAT_OPR(BPF_PROG_INFO, bpf_prog_info, false)
+ FEAT_OPR(BPF_PROG_INFO, bpf_prog_info, false),
+ FEAT_OPR(BPF_BTF, bpf_btf, false)
};

struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 0785c91b4c3a..9e7d931f7c0d 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -40,6 +40,7 @@ enum {
HEADER_MEM_TOPOLOGY,
HEADER_CLOCKID,
HEADER_BPF_PROG_INFO,
+ HEADER_BPF_BTF,
HEADER_LAST_FEATURE,
HEADER_FEAT_BITS = 256,
};
--
2.17.1