Messages in this thread | | | From | Song Liu <> | Subject | Re: [PATCH v2 perf,bpf 08/11] perf, bpf: save btf information as headers to perf.data | Date | Fri, 15 Feb 2019 17:25:01 +0000 |
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> On Feb 15, 2019, at 6:26 AM, Arnaldo Carvalho de Melo <acme@redhat.com> wrote: > > Em Thu, Feb 14, 2019 at 04:00:09PM -0800, Song Liu escreveu: >> This patch enables perf-record to save btf information as headers to >> perf.data A new header type HEADER_BTF is introduced for this data. > > Jiri, > > Wouldn't it be better for this HEADER_BTF to be introduced > already as an user space event, Song, see: > > tools/perf/util/event.h > > and: > > tools/perf/util/event.c > > perf_event__synthesize_cpu_map() > > - Arnaldo >
BTF would be short living for short living BPF programs. I guess saving them as header is easier than merging them with samples.
What's the benefit of saving them as user space events?
Thanks, Song
> >> Signed-off-by: Song Liu <songliubraving@fb.com> >> --- >> tools/perf/util/header.c | 99 +++++++++++++++++++++++++++++++++++++++- >> tools/perf/util/header.h | 1 + >> 2 files changed, 99 insertions(+), 1 deletion(-) >> >> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c >> index 2ae76a9d06f6..3f1562afe8e5 100644 >> --- a/tools/perf/util/header.c >> +++ b/tools/perf/util/header.c >> @@ -1125,6 +1125,45 @@ static int write_bpf_prog_info(struct feat_fd *ff, >> return ret; >> } >> >> +static int write_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; >> + u32 count = 0; >> + int ret; >> + >> + down_read(&env->bpf_info_lock); >> + >> + root = &env->btfs; >> + next = rb_first(root); >> + while (next) { >> + ++count; >> + next = rb_next(next); >> + } >> + >> + ret = do_write(ff, &count, sizeof(count)); >> + >> + if (ret < 0) >> + goto out; >> + >> + 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, >> + sizeof(struct btf_node) + node->data_size); >> + if (ret < 0) >> + goto out; >> + } >> +out: >> + up_read(&env->bpf_info_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; >> @@ -1628,6 +1667,28 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp) >> up_read(&env->bpf_info_lock); >> } >> >> +static void print_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_info_lock); >> + >> + root = &env->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, "# bpf_prog_info of id %u\n", node->id); >> + } >> + >> + up_read(&env->bpf_info_lock); >> +} >> + >> static void free_event_desc(struct perf_evsel *events) >> { >> struct perf_evsel *evsel; >> @@ -2723,6 +2784,41 @@ static int process_bpf_prog_info(struct feat_fd *ff, >> return err; >> } >> >> +static int process_btf(struct feat_fd *ff, void *data __maybe_unused) >> +{ >> + struct perf_env *env = &ff->ph->env; >> + u32 count, i; >> + >> + if (do_read_u32(ff, &count)) >> + return -1; >> + >> + down_write(&env->bpf_info_lock); >> + >> + for (i = 0; i < count; ++i) { >> + struct btf_node btf_node; >> + struct btf_node *node; >> + >> + if (__do_read(ff, &btf_node, sizeof(struct btf_node))) >> + return -1; >> + >> + node = malloc(sizeof(struct btf_node) + btf_node.data_size); >> + if (!node) >> + return -1; >> + >> + node->id = btf_node.id; >> + node->data_size = btf_node.data_size; >> + >> + if (__do_read(ff, node->data, btf_node.data_size)) { >> + free(node); >> + return -1; >> + } >> + perf_env__insert_btf(env, node); >> + } >> + >> + up_write(&env->bpf_info_lock); >> + return 0; >> +} >> + >> struct feature_ops { >> int (*write)(struct feat_fd *ff, struct perf_evlist *evlist); >> void (*print)(struct feat_fd *ff, FILE *fp); >> @@ -2783,7 +2879,8 @@ 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(BTF, btf, false) >> }; >> >> struct header_print_data { >> diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h >> index 0785c91b4c3a..ba51d8e43c53 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_BTF, >> HEADER_LAST_FEATURE, >> HEADER_FEAT_BITS = 256, >> }; >> -- >> 2.17.1
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