From a70a1123174ab592c5fa8ecf09f9fad9b335b872 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Mon, 11 Mar 2019 22:30:45 -0700 Subject: [PATCH] perf bpf: Save BTF information as headers to perf.data 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. Committer testing: As root, being on the kernel sources top level directory, run: # perf trace -e tools/perf/examples/bpf/augmented_raw_syscalls.c -e *msg Just to compile and load a BPF program that attaches to the raw_syscalls:sys_{enter,exit} tracepoints to trace the syscalls ending in "msg" (recvmsg, sendmsg, recvmmsg, sendmmsg, etc). Make sure you have a recent enough clang, say version 9, to get the BTF ELF sections needed for this testing: # clang --version | head -1 clang version 9.0.0 (https://git.llvm.org/git/clang.git/ 7906282d3afec5dfdc2b27943fd6c0309086c507) (https://git.llvm.org/git/llvm.git/ a1b5de1ff8ae8bc79dc8e86e1f82565229bd0500) # readelf -SW tools/perf/examples/bpf/augmented_raw_syscalls.o | grep BTF [22] .BTF PROGBITS 0000000000000000 000ede 000b0e 00 0 0 1 [23] .BTF.ext PROGBITS 0000000000000000 0019ec 0002a0 00 0 0 1 [24] .rel.BTF.ext REL 0000000000000000 002fa8 000270 10 30 23 8 Then do a systemwide perf record session for a few seconds: # perf record -a sleep 2s Then look at: # perf report --header-only | grep b[pt]f # event : name = cycles:ppp, , id = { 1116204, 1116205, 1116206, 1116207, 1116208, 1116209, 1116210, 1116211 }, size = 112, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|PERIOD, read_format = ID, disabled = 1, inherit = 1, mmap = 1, comm = 1, freq = 1, enable_on_exec = 1, task = 1, precise_ip = 3, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1, ksymbol = 1, bpf_event = 1 # bpf_prog_info of id 13 # bpf_prog_info of id 14 # bpf_prog_info of id 15 # bpf_prog_info of id 16 # bpf_prog_info of id 17 # bpf_prog_info of id 18 # bpf_prog_info of id 21 # bpf_prog_info of id 22 # bpf_prog_info of id 51 # bpf_prog_info of id 52 # btf info of id 8 # We need to show more info about these BPF and BTF entries , but that can be done later. Signed-off-by: Song Liu Reviewed-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stanislav Fomichev Cc: kernel-team@fb.com Link: http://lkml.kernel.org/r/20190312053051.2690567-10-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 e6a81af516f6..01dda2f65d36 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -928,6 +928,39 @@ static int write_bpf_prog_info(struct feat_fd *ff __maybe_unused, } #endif // HAVE_LIBBPF_SUPPORT +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; @@ -1442,6 +1475,28 @@ 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; @@ -2564,6 +2619,49 @@ static int process_bpf_prog_info(struct feat_fd *ff __maybe_unused, void *data _ } #endif // HAVE_LIBBPF_SUPPORT +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); @@ -2625,7 +2723,8 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = { FEAT_OPR(MEM_TOPOLOGY, mem_topology, true), FEAT_OPR(CLOCKID, clockid, false), FEAT_OPN(DIR_FORMAT, dir_format, 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 1dc85f0f895d..386da49e1bfa 100644 --- a/tools/perf/util/header.h +++ b/tools/perf/util/header.h @@ -41,6 +41,7 @@ enum { HEADER_CLOCKID, HEADER_DIR_FORMAT, HEADER_BPF_PROG_INFO, + HEADER_BPF_BTF, HEADER_LAST_FEATURE, HEADER_FEAT_BITS = 256, };