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Commit 606f972b authored by Song Liu's avatar Song Liu Committed by Arnaldo Carvalho de Melo
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perf bpf: Save bpf_prog_info information as headers to perf.data 



This patch enables perf-record to save bpf_prog_info information as
headers to perf.data. A new header type HEADER_BPF_PROG_INFO 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).

Then do a systemwide perf record session for a few seconds:

  # perf record -a sleep 2s

Then look at:

  # perf report --header-only | grep -i bpf
  # 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 208
  # bpf_prog_info of id 209
  #

We need to show more info about these programs, like bpftool does for
the ones running on the system, i.e. 'perf record/perf report' become a
way of saving the BPF state in a machine to then analyse on another,
together with all the other information that is already saved in the
perf.data header:

  # perf report --header-only
  # ========
  # captured on    : Tue Mar 12 11:42:13 2019
  # header version : 1
  # data offset    : 296
  # data size      : 16294184
  # feat offset    : 16294480
  # hostname : quaco
  # os release : 5.0.0+
  # perf version : 5.0.gd783c8
  # arch : x86_64
  # nrcpus online : 8
  # nrcpus avail : 8
  # cpudesc : Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
  # cpuid : GenuineIntel,6,142,10
  # total memory : 24555720 kB
  # cmdline : /home/acme/bin/perf (deleted) record -a
  # event : name = cycles:ppp, , id = { 3190123, 3190124, 3190125, 31901264, 3190127, 3190128, 3190129, 3190130 }, size = 112, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|CPU|PERIOD, read_format = ID, disabled = 1, inherit = 1, mmap = 1, comm = 1, freq = 1, task = 1, precise_ip = 3, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1
  # CPU_TOPOLOGY info available, use -I to display
  # NUMA_TOPOLOGY info available, use -I to display
  # pmu mappings: intel_pt = 8, software = 1, power = 11, uprobe = 7, uncore_imc = 12, cpu = 4, cstate_core = 18, uncore_cbox_2 = 15, breakpoint = 5, uncore_cbox_0 = 13, tracepoint = 2, cstate_pkg = 19, uncore_arb = 17, kprobe = 6, i915 = 10, msr = 9, uncore_cbox_3 = 16, uncore_cbox_1 = 14
  # CACHE info available, use -I to display
  # time of first sample : 116392.441701
  # time of last sample : 116400.932584
  # sample duration :   8490.883 ms
  # MEM_TOPOLOGY info available, use -I to display
  # 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 208
  # bpf_prog_info of id 209
  # missing features: TRACING_DATA BRANCH_STACK GROUP_DESC AUXTRACE STAT CLOCKID DIR_FORMAT
  # ========
  #

Committer notes:

We can't use the libbpf unconditionally, as the build may have been with
NO_LIBBPF, when we end up with linking errors, so provide dummy
{process,write}_bpf_prog_info() wrapped by HAVE_LIBBPF_SUPPORT for that
case.

Printing are not affected by this, so can continue as is.

Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Reviewed-by: default avatarJiri Olsa <jolsa@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: kernel-team@fb.com
Link: http://lkml.kernel.org/r/20190312053051.2690567-8-songliubraving@fb.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e4378f0c

tools/perf/util/header.c

+152 −1
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <sys/utsname.h>

#include <linux/time64.h>

#include <dirent.h>

#include <bpf/libbpf.h>



#include "evlist.h"

#include "evsel.h"
@@ -40,6 +41,7 @@ 
#include "time-utils.h"

#include "units.h"

#include "cputopo.h"

#include "bpf-event.h"



#include "sane_ctype.h"
@@ -876,6 +878,56 @@ static int write_dir_format(struct feat_fd *ff, 
	return do_write(ff, &data->dir.version, sizeof(data->dir.version));

}



#ifdef HAVE_LIBBPF_SUPPORT

static int write_bpf_prog_info(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.infos_cnt,

		       sizeof(env->bpf_progs.infos_cnt));

	if (ret < 0)

		goto out;



	root = &env->bpf_progs.infos;

	next = rb_first(root);

	while (next) {

		struct bpf_prog_info_node *node;

		size_t len;



		node = rb_entry(next, struct bpf_prog_info_node, rb_node);

		next = rb_next(&node->rb_node);

		len = sizeof(struct bpf_prog_info_linear) +

			node->info_linear->data_len;



		/* before writing to file, translate address to offset */

		bpf_program__bpil_addr_to_offs(node->info_linear);

		ret = do_write(ff, node->info_linear, len);

		/*

		 * translate back to address even when do_write() fails,

		 * so that this function never changes the data.

		 */

		bpf_program__bpil_offs_to_addr(node->info_linear);

		if (ret < 0)

			goto out;

	}

out:

	up_read(&env->bpf_progs.lock);

	return ret;

}

#else // HAVE_LIBBPF_SUPPORT

static int write_bpf_prog_info(struct feat_fd *ff __maybe_unused,

			       struct perf_evlist *evlist __maybe_unused)

{

	return 0;

}

#endif // HAVE_LIBBPF_SUPPORT



static int cpu_cache_level__sort(const void *a, const void *b)

{

	struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
@@ -1367,6 +1419,29 @@ static void print_dir_format(struct feat_fd *ff, FILE *fp) 
	fprintf(fp, "# directory data version : %"PRIu64"\n", data->dir.version);

}



static void print_bpf_prog_info(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.infos;

	next = rb_first(root);



	while (next) {

		struct bpf_prog_info_node *node;



		node = rb_entry(next, struct bpf_prog_info_node, rb_node);

		next = rb_next(&node->rb_node);

		fprintf(fp, "# bpf_prog_info of id %u\n",

			node->info_linear->info.id);

	}



	up_read(&env->bpf_progs.lock);

}



static void free_event_desc(struct perf_evsel *events)

{

	struct perf_evsel *evsel;
@@ -2414,6 +2489,81 @@ static int process_dir_format(struct feat_fd *ff, 
	return do_read_u64(ff, &data->dir.version);

}



#ifdef HAVE_LIBBPF_SUPPORT

static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)

{

	struct bpf_prog_info_linear *info_linear;

	struct bpf_prog_info_node *info_node;

	struct perf_env *env = &ff->ph->env;

	u32 count, i;

	int err = -1;



	if (ff->ph->needs_swap) {

		pr_warning("interpreting bpf_prog_info 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) {

		u32 info_len, data_len;



		info_linear = NULL;

		info_node = NULL;

		if (do_read_u32(ff, &info_len))

			goto out;

		if (do_read_u32(ff, &data_len))

			goto out;



		if (info_len > sizeof(struct bpf_prog_info)) {

			pr_warning("detected invalid bpf_prog_info\n");

			goto out;

		}



		info_linear = malloc(sizeof(struct bpf_prog_info_linear) +

				     data_len);

		if (!info_linear)

			goto out;

		info_linear->info_len = sizeof(struct bpf_prog_info);

		info_linear->data_len = data_len;

		if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))

			goto out;

		if (__do_read(ff, &info_linear->info, info_len))

			goto out;

		if (info_len < sizeof(struct bpf_prog_info))

			memset(((void *)(&info_linear->info)) + info_len, 0,

			       sizeof(struct bpf_prog_info) - info_len);



		if (__do_read(ff, info_linear->data, data_len))

			goto out;



		info_node = malloc(sizeof(struct bpf_prog_info_node));

		if (!info_node)

			goto out;



		/* after reading from file, translate offset to address */

		bpf_program__bpil_offs_to_addr(info_linear);

		info_node->info_linear = info_linear;

		perf_env__insert_bpf_prog_info(env, info_node);

	}



	return 0;

out:

	free(info_linear);

	free(info_node);

	up_write(&env->bpf_progs.lock);

	return err;

}

#else // HAVE_LIBBPF_SUPPORT

static int process_bpf_prog_info(struct feat_fd *ff __maybe_unused, void *data __maybe_unused)

{

	return 0;

}

#endif // HAVE_LIBBPF_SUPPORT



struct feature_ops {

	int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);

	void (*print)(struct feat_fd *ff, FILE *fp);
@@ -2474,7 +2624,8 @@ 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_OPN(DIR_FORMAT,	dir_format,	false)

	FEAT_OPN(DIR_FORMAT,	dir_format,	false),

	FEAT_OPR(BPF_PROG_INFO, bpf_prog_info,  false)

};



struct header_print_data {

tools/perf/util/header.h

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ enum { 
	HEADER_MEM_TOPOLOGY,

	HEADER_CLOCKID,

	HEADER_DIR_FORMAT,

	HEADER_BPF_PROG_INFO,

	HEADER_LAST_FEATURE,

	HEADER_FEAT_BITS	= 256,

};