Re: [PATCH v7 3/3] perf-stat: enable counting events for BPF programs

From: Arnaldo Carvalho de Melo
Date: Mon Jan 18 2021 - 14:39:57 EST

Em Tue, Dec 29, 2020 at 01:42:14PM -0800, Song Liu escreveu:
> Introduce perf-stat -b option, which counts events for BPF programs, like:
>
> [root@localhost ~]# ~/perf stat -e ref-cycles,cycles -b 254 -I 1000
> 1.487903822 115,200 ref-cycles
> 1.487903822 86,012 cycles
> 2.489147029 80,560 ref-cycles
> 2.489147029 73,784 cycles
> 3.490341825 60,720 ref-cycles
> 3.490341825 37,797 cycles
> 4.491540887 37,120 ref-cycles
> 4.491540887 31,963 cycles
>
> The example above counts cycles and ref-cycles of BPF program of id 254.
> This is similar to bpftool-prog-profile command, but more flexible.

So trying to get back to this after vacation:

[root@five ~]# perf stat -vvv -e cycles -b 103
Control descriptor is not initialized
libbpf: elf: skipping unrecognized data section(9) .eh_frame
libbpf: elf: skipping relo section(15) .rel.eh_frame for section(9) .eh_frame
libbpf: load bpf program failed: Invalid argument
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Cannot recursively attach
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0

libbpf: -- END LOG --
libbpf: failed to load program 'fentry_XXX'
libbpf: failed to load object 'bpf_prog_profiler_bpf'
libbpf: failed to load BPF skeleton 'bpf_prog_profiler_bpf': -4007
bpf_prog_profiler_bpf__load failed
[root@five ~]#

[root@five perf]# tools/bpf/runqslower/.output/
bpftool/ libbpf/ runqslower
[root@five perf]# tools/bpf/runqslower/.output/runqslower
libbpf: elf: skipping unrecognized data section(10) .eh_frame
libbpf: elf: skipping relo section(17) .rel.eh_frame for section(10) .eh_frame
Tracing run queue latency higher than 10000 us
TIME COMM PID LAT(us)

[root@five ~]# bpftool prog
6: tracing name dump_bpf_map tag e54c922dfa54f65f gpl
loaded_at 2021-01-15T11:14:38-0300 uid 0
xlated 256B jited 154B memlock 4096B map_ids 3
btf_id 6
8: tracing name dump_bpf_prog tag 4cb5558b902ee92e gpl
loaded_at 2021-01-15T11:14:38-0300 uid 0
xlated 520B jited 301B memlock 4096B map_ids 3
btf_id 6
80: cgroup_device tag 8b9c33f36f812014 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 744B jited 447B memlock 4096B
81: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
82: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
83: cgroup_device tag ee0e253c78993a24 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 416B jited 255B memlock 4096B
84: cgroup_device tag e3dbd137be8d6168 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 504B jited 309B memlock 4096B
85: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
86: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
87: cgroup_device tag c8b47a902f1cc68b gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 464B jited 288B memlock 4096B
88: cgroup_device tag 0ecd07b7b633809f gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 496B jited 307B memlock 4096B
89: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
90: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
91: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
92: cgroup_skb tag 6deef7357e7b4530 gpl
loaded_at 2021-01-17T18:35:22-0300 uid 0
xlated 64B jited 54B memlock 4096B
100: tracing name handle__sched_w tag 00ba1f1d332f5a57 gpl
loaded_at 2021-01-18T16:34:00-0300 uid 0
xlated 152B jited 93B memlock 4096B map_ids 11,9
btf_id 248
102: tracing name handle__sched_w tag 00ba1f1d332f5a57 gpl
loaded_at 2021-01-18T16:34:00-0300 uid 0
xlated 152B jited 93B memlock 4096B map_ids 11,9
btf_id 248
103: tracing name handle__sched_s tag a4ac42153fd49be2 gpl
loaded_at 2021-01-18T16:34:00-0300 uid 0
xlated 560B jited 332B memlock 4096B map_ids 11,9,10
btf_id 248
[root@five ~]# perf stat -vvv -e cycles -b 92
Control descriptor is not initialized
libbpf: elf: skipping unrecognized data section(9) .eh_frame
libbpf: elf: skipping relo section(15) .rel.eh_frame for section(9) .eh_frame
prog FD 3 doesn't have valid btf
Failed to get program name for bpf prog 92. Does it have BTF?
[root@five ~]# perf stat -vvv -e cycles -b 103
Control descriptor is not initialized
libbpf: elf: skipping unrecognized data section(9) .eh_frame
libbpf: elf: skipping relo section(15) .rel.eh_frame for section(9) .eh_frame
libbpf: load bpf program failed: Invalid argument
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Cannot recursively attach
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0

libbpf: -- END LOG --
libbpf: failed to load program 'fentry_XXX'
libbpf: failed to load object 'bpf_prog_profiler_bpf'
libbpf: failed to load BPF skeleton 'bpf_prog_profiler_bpf': -4007
bpf_prog_profiler_bpf__load failed
[root@five ~]# perf stat -vvv -e cycles -b 102
Control descriptor is not initialized
libbpf: elf: skipping unrecognized data section(9) .eh_frame
libbpf: elf: skipping relo section(15) .rel.eh_frame for section(9) .eh_frame
libbpf: load bpf program failed: Invalid argument
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Cannot recursively attach
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0

libbpf: -- END LOG --
libbpf: failed to load program 'fentry_XXX'
libbpf: failed to load object 'bpf_prog_profiler_bpf'
libbpf: failed to load BPF skeleton 'bpf_prog_profiler_bpf': -4007
bpf_prog_profiler_bpf__load failed
[root@five ~]#
[root@five ~]# perf stat -vvv -e cycles -b 6
Control descriptor is not initialized
libbpf: elf: skipping unrecognized data section(9) .eh_frame
libbpf: elf: skipping relo section(15) .rel.eh_frame for section(9) .eh_frame
libbpf: load bpf program failed: Invalid argument
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Cannot recursively attach
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0

libbpf: -- END LOG --
libbpf: failed to load program 'fentry_XXX'
libbpf: failed to load object 'bpf_prog_profiler_bpf'
libbpf: failed to load BPF skeleton 'bpf_prog_profiler_bpf': -4007
bpf_prog_profiler_bpf__load failed
[root@five ~]#

So no more segfaults, but still something to look at, I'm pushing my
local perf/core to tmp.perf/core, please take a look.

- Arnaldo

> perf-stat -b creates per-cpu perf_event and loads fentry/fexit BPF
> programs (monitor-progs) to the target BPF program (target-prog). The
> monitor-progs read perf_event before and after the target-prog, and
> aggregate the difference in a BPF map. Then the user space reads data
> from these maps.
>
> A new struct bpf_counter is introduced to provide common interface that
> uses BPF programs/maps to count perf events.
>
> Signed-off-by: Song Liu <songliubraving@xxxxxx>
> ---
> tools/perf/Documentation/perf-stat.txt | 18 +
> tools/perf/Makefile.perf | 2 +-
> tools/perf/builtin-stat.c | 82 ++++-
> tools/perf/util/Build | 1 +
> tools/perf/util/bpf_counter.c | 309 ++++++++++++++++++
> tools/perf/util/bpf_counter.h | 72 ++++
> .../util/bpf_skel/bpf_prog_profiler.bpf.c | 93 ++++++
> tools/perf/util/evsel.c | 9 +
> tools/perf/util/evsel.h | 5 +
> tools/perf/util/python.c | 21 ++
> tools/perf/util/stat-display.c | 4 +-
> tools/perf/util/stat.c | 2 +-
> tools/perf/util/target.c | 34 +-
> tools/perf/util/target.h | 10 +
> 14 files changed, 644 insertions(+), 18 deletions(-)
> create mode 100644 tools/perf/util/bpf_counter.c
> create mode 100644 tools/perf/util/bpf_counter.h
> create mode 100644 tools/perf/util/bpf_skel/bpf_prog_profiler.bpf.c
>
> diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
> index 5d4a673d7621a..98a4dfd3b2dc9 100644
> --- a/tools/perf/Documentation/perf-stat.txt
> +++ b/tools/perf/Documentation/perf-stat.txt
> @@ -75,6 +75,24 @@ report::
> --tid=<tid>::
> stat events on existing thread id (comma separated list)
>
> +-b::
> +--bpf-prog::
> + stat events on existing bpf program id (comma separated list),
> + requiring root rights. bpftool-prog could be used to find program
> + id all bpf programs in the system. For example:
> +
> + # bpftool prog | head -n 1
> + 17247: tracepoint name sys_enter tag 192d548b9d754067 gpl
> +
> + # perf stat -e cycles,instructions --bpf-prog 17247 --timeout 1000
> +
> + Performance counter stats for 'BPF program(s) 17247':
> +
> + 85,967 cycles
> + 28,982 instructions # 0.34 insn per cycle
> +
> + 1.102235068 seconds time elapsed
> +
> ifdef::HAVE_LIBPFM[]
> --pfm-events events::
> Select a PMU event using libpfm4 syntax (see http://perfmon2.sf.net)
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index d182a2dbb9bbd..8c4e039c3b813 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -1015,7 +1015,7 @@ python-clean:
>
> SKEL_OUT := $(abspath $(OUTPUT)util/bpf_skel)
> SKEL_TMP_OUT := $(abspath $(SKEL_OUT)/.tmp)
> -SKELETONS :=
> +SKELETONS := $(SKEL_OUT)/bpf_prog_profiler.skel.h
>
> ifdef BUILD_BPF_SKEL
> BPFTOOL := $(SKEL_TMP_OUT)/bootstrap/bpftool
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 8cc24967bc273..3c054b8d4677c 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -67,6 +67,7 @@
> #include "util/top.h"
> #include "util/affinity.h"
> #include "util/pfm.h"
> +#include "util/bpf_counter.h"
> #include "asm/bug.h"
>
> #include <linux/time64.h>
> @@ -409,12 +410,32 @@ static int read_affinity_counters(struct timespec *rs)
> return 0;
> }
>
> +static int read_bpf_map_counters(void)
> +{
> + struct evsel *counter;
> + int err;
> +
> + evlist__for_each_entry(evsel_list, counter) {
> + err = bpf_counter__read(counter);
> + if (err)
> + return err;
> + }
> + return 0;
> +}
> +
> static void read_counters(struct timespec *rs)
> {
> struct evsel *counter;
> + int err;
>
> - if (!stat_config.stop_read_counter && (read_affinity_counters(rs) < 0))
> - return;
> + if (!stat_config.stop_read_counter) {
> + if (target__has_bpf(&target))
> + err = read_bpf_map_counters();
> + else
> + err = read_affinity_counters(rs);
> + if (err < 0)
> + return;
> + }
>
> evlist__for_each_entry(evsel_list, counter) {
> if (counter->err)
> @@ -496,11 +517,22 @@ static bool handle_interval(unsigned int interval, int *times)
> return false;
> }
>
> -static void enable_counters(void)
> +static int enable_counters(void)
> {
> + struct evsel *evsel;
> + int err;
> +
> + if (target__has_bpf(&target)) {
> + evlist__for_each_entry(evsel_list, evsel) {
> + err = bpf_counter__enable(evsel);
> + if (err)
> + return err;
> + }
> + }
> +
> if (stat_config.initial_delay < 0) {
> pr_info(EVLIST_DISABLED_MSG);
> - return;
> + return 0;
> }
>
> if (stat_config.initial_delay > 0) {
> @@ -518,6 +550,7 @@ static void enable_counters(void)
> if (stat_config.initial_delay > 0)
> pr_info(EVLIST_ENABLED_MSG);
> }
> + return 0;
> }
>
> static void disable_counters(void)
> @@ -720,7 +753,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
> const bool forks = (argc > 0);
> bool is_pipe = STAT_RECORD ? perf_stat.data.is_pipe : false;
> struct affinity affinity;
> - int i, cpu;
> + int i, cpu, err;
> bool second_pass = false;
>
> if (forks) {
> @@ -737,6 +770,13 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
> if (affinity__setup(&affinity) < 0)
> return -1;
>
> + if (target__has_bpf(&target)) {
> + evlist__for_each_entry(evsel_list, counter) {
> + if (bpf_counter__load(counter, &target))
> + return -1;
> + }
> + }
> +
> evlist__for_each_cpu (evsel_list, i, cpu) {
> affinity__set(&affinity, cpu);
>
> @@ -850,7 +890,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
> }
>
> if (STAT_RECORD) {
> - int err, fd = perf_data__fd(&perf_stat.data);
> + int fd = perf_data__fd(&perf_stat.data);
>
> if (is_pipe) {
> err = perf_header__write_pipe(perf_data__fd(&perf_stat.data));
> @@ -876,7 +916,9 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
>
> if (forks) {
> evlist__start_workload(evsel_list);
> - enable_counters();
> + err = enable_counters();
> + if (err)
> + return -1;
>
> if (interval || timeout || evlist__ctlfd_initialized(evsel_list))
> status = dispatch_events(forks, timeout, interval, &times);
> @@ -895,7 +937,9 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
> if (WIFSIGNALED(status))
> psignal(WTERMSIG(status), argv[0]);
> } else {
> - enable_counters();
> + err = enable_counters();
> + if (err)
> + return -1;
> status = dispatch_events(forks, timeout, interval, &times);
> }
>
> @@ -1085,6 +1129,10 @@ static struct option stat_options[] = {
> "stat events on existing process id"),
> OPT_STRING('t', "tid", &target.tid, "tid",
> "stat events on existing thread id"),
> +#ifdef HAVE_BPF_SKEL
> + OPT_STRING('b', "bpf-prog", &target.bpf_str, "bpf-prog-id",
> + "stat events on existing bpf program id"),
> +#endif
> OPT_BOOLEAN('a', "all-cpus", &target.system_wide,
> "system-wide collection from all CPUs"),
> OPT_BOOLEAN('g', "group", &group,
> @@ -2064,11 +2112,12 @@ int cmd_stat(int argc, const char **argv)
> "perf stat [<options>] [<command>]",
> NULL
> };
> - int status = -EINVAL, run_idx;
> + int status = -EINVAL, run_idx, err;
> const char *mode;
> FILE *output = stderr;
> unsigned int interval, timeout;
> const char * const stat_subcommands[] = { "record", "report" };
> + char errbuf[BUFSIZ];
>
> setlocale(LC_ALL, "");
>
> @@ -2179,6 +2228,12 @@ int cmd_stat(int argc, const char **argv)
> } else if (big_num_opt == 0) /* User passed --no-big-num */
> stat_config.big_num = false;
>
> + err = target__validate(&target);
> + if (err) {
> + target__strerror(&target, err, errbuf, BUFSIZ);
> + pr_warning("%s\n", errbuf);
> + }
> +
> setup_system_wide(argc);
>
> /*
> @@ -2252,8 +2307,6 @@ int cmd_stat(int argc, const char **argv)
> }
> }
>
> - target__validate(&target);
> -
> if ((stat_config.aggr_mode == AGGR_THREAD) && (target.system_wide))
> target.per_thread = true;
>
> @@ -2384,9 +2437,10 @@ int cmd_stat(int argc, const char **argv)
> * tools remain -acme
> */
> int fd = perf_data__fd(&perf_stat.data);
> - int err = perf_event__synthesize_kernel_mmap((void *)&perf_stat,
> - process_synthesized_event,
> - &perf_stat.session->machines.host);
> +
> + err = perf_event__synthesize_kernel_mmap((void *)&perf_stat,
> + process_synthesized_event,
> + &perf_stat.session->machines.host);
> if (err) {
> pr_warning("Couldn't synthesize the kernel mmap record, harmless, "
> "older tools may produce warnings about this file\n.");
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index e2563d0154eb6..188521f343470 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -135,6 +135,7 @@ perf-y += clockid.o
>
> perf-$(CONFIG_LIBBPF) += bpf-loader.o
> perf-$(CONFIG_LIBBPF) += bpf_map.o
> +perf-$(CONFIG_PERF_BPF_SKEL) += bpf_counter.o
> perf-$(CONFIG_BPF_PROLOGUE) += bpf-prologue.o
> perf-$(CONFIG_LIBELF) += symbol-elf.o
> perf-$(CONFIG_LIBELF) += probe-file.o
> diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c
> new file mode 100644
> index 0000000000000..8c977f038f497
> --- /dev/null
> +++ b/tools/perf/util/bpf_counter.c
> @@ -0,0 +1,309 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/* Copyright (c) 2019 Facebook */
> +
> +#include <assert.h>
> +#include <limits.h>
> +#include <unistd.h>
> +#include <sys/time.h>
> +#include <sys/resource.h>
> +#include <linux/err.h>
> +#include <linux/zalloc.h>
> +#include <bpf/bpf.h>
> +#include <bpf/btf.h>
> +#include <bpf/libbpf.h>
> +
> +#include "bpf_counter.h"
> +#include "counts.h"
> +#include "debug.h"
> +#include "evsel.h"
> +#include "target.h"
> +
> +#include "bpf_skel/bpf_prog_profiler.skel.h"
> +
> +static inline void *u64_to_ptr(__u64 ptr)
> +{
> + return (void *)(unsigned long)ptr;
> +}
> +
> +static void set_max_rlimit(void)
> +{
> + struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
> +
> + setrlimit(RLIMIT_MEMLOCK, &rinf);
> +}
> +
> +static struct bpf_counter *bpf_counter_alloc(void)
> +{
> + struct bpf_counter *counter;
> +
> + counter = zalloc(sizeof(*counter));
> + if (counter)
> + INIT_LIST_HEAD(&counter->list);
> + return counter;
> +}
> +
> +static int bpf_program_profiler__destroy(struct evsel *evsel)
> +{
> + struct bpf_counter *counter, *tmp;
> +
> + list_for_each_entry_safe(counter, tmp,
> + &evsel->bpf_counter_list, list) {
> + list_del_init(&counter->list);
> + bpf_prog_profiler_bpf__destroy(counter->skel);
> + free(counter);
> + }
> + assert(list_empty(&evsel->bpf_counter_list));
> +
> + return 0;
> +}
> +
> +static char *bpf_target_prog_name(int tgt_fd)
> +{
> + struct bpf_prog_info_linear *info_linear;
> + struct bpf_func_info *func_info;
> + const struct btf_type *t;
> + char *name = NULL;
> + struct btf *btf;
> +
> + info_linear = bpf_program__get_prog_info_linear(
> + tgt_fd, 1UL << BPF_PROG_INFO_FUNC_INFO);
> + if (IS_ERR_OR_NULL(info_linear)) {
> + pr_debug("failed to get info_linear for prog FD %d\n", tgt_fd);
> + return NULL;
> + }
> +
> + if (info_linear->info.btf_id == 0 ||
> + btf__get_from_id(info_linear->info.btf_id, &btf)) {
> + pr_debug("prog FD %d doesn't have valid btf\n", tgt_fd);
> + goto out;
> + }
> +
> + func_info = u64_to_ptr(info_linear->info.func_info);
> + t = btf__type_by_id(btf, func_info[0].type_id);
> + if (!t) {
> + pr_debug("btf %d doesn't have type %d\n",
> + info_linear->info.btf_id, func_info[0].type_id);
> + goto out;
> + }
> + name = strdup(btf__name_by_offset(btf, t->name_off));
> +out:
> + free(info_linear);
> + return name;
> +}
> +
> +static int bpf_program_profiler_load_one(struct evsel *evsel, u32 prog_id)
> +{
> + struct bpf_prog_profiler_bpf *skel;
> + struct bpf_counter *counter;
> + struct bpf_program *prog;
> + char *prog_name;
> + int prog_fd;
> + int err;
> +
> + prog_fd = bpf_prog_get_fd_by_id(prog_id);
> + if (prog_fd < 0) {
> + pr_err("Failed to open fd for bpf prog %u\n", prog_id);
> + return -1;
> + }
> + counter = bpf_counter_alloc();
> + if (!counter) {
> + close(prog_fd);
> + return -1;
> + }
> +
> + skel = bpf_prog_profiler_bpf__open();
> + if (!skel) {
> + pr_err("Failed to open bpf skeleton\n");
> + goto err_out;
> + }
> +
> + skel->rodata->num_cpu = evsel__nr_cpus(evsel);
> +
> + bpf_map__resize(skel->maps.events, evsel__nr_cpus(evsel));
> + bpf_map__resize(skel->maps.fentry_readings, 1);
> + bpf_map__resize(skel->maps.accum_readings, 1);
> +
> + prog_name = bpf_target_prog_name(prog_fd);
> + if (!prog_name) {
> + pr_err("Failed to get program name for bpf prog %u. Does it have BTF?\n", prog_id);
> + goto err_out;
> + }
> +
> + bpf_object__for_each_program(prog, skel->obj) {
> + err = bpf_program__set_attach_target(prog, prog_fd, prog_name);
> + if (err) {
> + pr_err("bpf_program__set_attach_target failed.\n"
> + "Does bpf prog %u have BTF?\n", prog_id);
> + goto err_out;
> + }
> + }
> + set_max_rlimit();
> + err = bpf_prog_profiler_bpf__load(skel);
> + if (err) {
> + pr_err("bpf_prog_profiler_bpf__load failed\n");
> + goto err_out;
> + }
> +
> + assert(skel != NULL);
> + counter->skel = skel;
> + list_add(&counter->list, &evsel->bpf_counter_list);
> + close(prog_fd);
> + return 0;
> +err_out:
> + bpf_prog_profiler_bpf__destroy(skel);
> + free(counter);
> + close(prog_fd);
> + return -1;
> +}
> +
> +static int bpf_program_profiler__load(struct evsel *evsel, struct target *target)
> +{
> + char *bpf_str, *bpf_str_, *tok, *saveptr = NULL, *p;
> + u32 prog_id;
> + int ret;
> +
> + bpf_str_ = bpf_str = strdup(target->bpf_str);
> + if (!bpf_str)
> + return -1;
> +
> + while ((tok = strtok_r(bpf_str, ",", &saveptr)) != NULL) {
> + prog_id = strtoul(tok, &p, 10);
> + if (prog_id == 0 || prog_id == UINT_MAX ||
> + (*p != '\0' && *p != ',')) {
> + pr_err("Failed to parse bpf prog ids %s\n",
> + target->bpf_str);
> + return -1;
> + }
> +
> + ret = bpf_program_profiler_load_one(evsel, prog_id);
> + if (ret) {
> + bpf_program_profiler__destroy(evsel);
> + free(bpf_str_);
> + return -1;
> + }
> + bpf_str = NULL;
> + }
> + free(bpf_str_);
> + return 0;
> +}
> +
> +static int bpf_program_profiler__enable(struct evsel *evsel)
> +{
> + struct bpf_counter *counter;
> + int ret;
> +
> + list_for_each_entry(counter, &evsel->bpf_counter_list, list) {
> + assert(counter->skel != NULL);
> + ret = bpf_prog_profiler_bpf__attach(counter->skel);
> + if (ret) {
> + bpf_program_profiler__destroy(evsel);
> + return ret;
> + }
> + }
> + return 0;
> +}
> +
> +static int bpf_program_profiler__read(struct evsel *evsel)
> +{
> + int num_cpu = evsel__nr_cpus(evsel);
> + struct bpf_perf_event_value values[num_cpu];
> + struct bpf_counter *counter;
> + int reading_map_fd;
> + __u32 key = 0;
> + int err, cpu;
> +
> + if (list_empty(&evsel->bpf_counter_list))
> + return -EAGAIN;
> +
> + for (cpu = 0; cpu < num_cpu; cpu++) {
> + perf_counts(evsel->counts, cpu, 0)->val = 0;
> + perf_counts(evsel->counts, cpu, 0)->ena = 0;
> + perf_counts(evsel->counts, cpu, 0)->run = 0;
> + }
> + list_for_each_entry(counter, &evsel->bpf_counter_list, list) {
> + struct bpf_prog_profiler_bpf *skel = counter->skel;
> +
> + assert(skel != NULL);
> + reading_map_fd = bpf_map__fd(skel->maps.accum_readings);
> +
> + err = bpf_map_lookup_elem(reading_map_fd, &key, values);
> + if (err) {
> + pr_err("failed to read value\n");
> + return err;
> + }
> +
> + for (cpu = 0; cpu < num_cpu; cpu++) {
> + perf_counts(evsel->counts, cpu, 0)->val += values[cpu].counter;
> + perf_counts(evsel->counts, cpu, 0)->ena += values[cpu].enabled;
> + perf_counts(evsel->counts, cpu, 0)->run += values[cpu].running;
> + }
> + }
> + return 0;
> +}
> +
> +static int bpf_program_profiler__install_pe(struct evsel *evsel, int cpu,
> + int fd)
> +{
> + struct bpf_prog_profiler_bpf *skel;
> + struct bpf_counter *counter;
> + int ret;
> +
> + list_for_each_entry(counter, &evsel->bpf_counter_list, list) {
> + skel = counter->skel;
> + assert(skel != NULL);
> +
> + ret = bpf_map_update_elem(bpf_map__fd(skel->maps.events),
> + &cpu, &fd, BPF_ANY);
> + if (ret)
> + return ret;
> + }
> + return 0;
> +}
> +
> +struct bpf_counter_ops bpf_program_profiler_ops = {
> + .load = bpf_program_profiler__load,
> + .enable = bpf_program_profiler__enable,
> + .read = bpf_program_profiler__read,
> + .destroy = bpf_program_profiler__destroy,
> + .install_pe = bpf_program_profiler__install_pe,
> +};
> +
> +int bpf_counter__install_pe(struct evsel *evsel, int cpu, int fd)
> +{
> + if (list_empty(&evsel->bpf_counter_list))
> + return 0;
> + return evsel->bpf_counter_ops->install_pe(evsel, cpu, fd);
> +}
> +
> +int bpf_counter__load(struct evsel *evsel, struct target *target)
> +{
> + if (target__has_bpf(target))
> + evsel->bpf_counter_ops = &bpf_program_profiler_ops;
> +
> + if (evsel->bpf_counter_ops)
> + return evsel->bpf_counter_ops->load(evsel, target);
> + return 0;
> +}
> +
> +int bpf_counter__enable(struct evsel *evsel)
> +{
> + if (list_empty(&evsel->bpf_counter_list))
> + return 0;
> + return evsel->bpf_counter_ops->enable(evsel);
> +}
> +
> +int bpf_counter__read(struct evsel *evsel)
> +{
> + if (list_empty(&evsel->bpf_counter_list))
> + return -EAGAIN;
> + return evsel->bpf_counter_ops->read(evsel);
> +}
> +
> +void bpf_counter__destroy(struct evsel *evsel)
> +{
> + if (list_empty(&evsel->bpf_counter_list))
> + return;
> + evsel->bpf_counter_ops->destroy(evsel);
> + evsel->bpf_counter_ops = NULL;
> +}
> diff --git a/tools/perf/util/bpf_counter.h b/tools/perf/util/bpf_counter.h
> new file mode 100644
> index 0000000000000..2eca210e5dc16
> --- /dev/null
> +++ b/tools/perf/util/bpf_counter.h
> @@ -0,0 +1,72 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __PERF_BPF_COUNTER_H
> +#define __PERF_BPF_COUNTER_H 1
> +
> +#include <linux/list.h>
> +
> +struct evsel;
> +struct target;
> +struct bpf_counter;
> +
> +typedef int (*bpf_counter_evsel_op)(struct evsel *evsel);
> +typedef int (*bpf_counter_evsel_target_op)(struct evsel *evsel,
> + struct target *target);
> +typedef int (*bpf_counter_evsel_install_pe_op)(struct evsel *evsel,
> + int cpu,
> + int fd);
> +
> +struct bpf_counter_ops {
> + bpf_counter_evsel_target_op load;
> + bpf_counter_evsel_op enable;
> + bpf_counter_evsel_op read;
> + bpf_counter_evsel_op destroy;
> + bpf_counter_evsel_install_pe_op install_pe;
> +};
> +
> +struct bpf_counter {
> + void *skel;
> + struct list_head list;
> +};
> +
> +#ifdef HAVE_BPF_SKEL
> +
> +int bpf_counter__load(struct evsel *evsel, struct target *target);
> +int bpf_counter__enable(struct evsel *evsel);
> +int bpf_counter__read(struct evsel *evsel);
> +void bpf_counter__destroy(struct evsel *evsel);
> +int bpf_counter__install_pe(struct evsel *evsel, int cpu, int fd);
> +
> +#else /* HAVE_BPF_SKEL */
> +
> +#include<linux/err.h>
> +
> +static inline int bpf_counter__load(struct evsel *evsel __maybe_unused,
> + struct target *target __maybe_unused)
> +{
> + return 0;
> +}
> +
> +static inline int bpf_counter__enable(struct evsel *evsel __maybe_unused)
> +{
> + return 0;
> +}
> +
> +static inline int bpf_counter__read(struct evsel *evsel __maybe_unused)
> +{
> + return -EAGAIN;
> +}
> +
> +static inline void bpf_counter__destroy(struct evsel *evsel __maybe_unused)
> +{
> +}
> +
> +static inline int bpf_counter__install_pe(struct evsel *evsel __maybe_unused,
> + int cpu __maybe_unused,
> + int fd __maybe_unused)
> +{
> + return 0;
> +}
> +
> +#endif /* HAVE_BPF_SKEL */
> +
> +#endif /* __PERF_BPF_COUNTER_H */
> diff --git a/tools/perf/util/bpf_skel/bpf_prog_profiler.bpf.c b/tools/perf/util/bpf_skel/bpf_prog_profiler.bpf.c
> new file mode 100644
> index 0000000000000..c7cec92d02360
> --- /dev/null
> +++ b/tools/perf/util/bpf_skel/bpf_prog_profiler.bpf.c
> @@ -0,0 +1,93 @@
> +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +// Copyright (c) 2020 Facebook
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +
> +/* map of perf event fds, num_cpu * num_metric entries */
> +struct {
> + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
> + __uint(key_size, sizeof(__u32));
> + __uint(value_size, sizeof(int));
> +} events SEC(".maps");
> +
> +/* readings at fentry */
> +struct {
> + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
> + __uint(key_size, sizeof(__u32));
> + __uint(value_size, sizeof(struct bpf_perf_event_value));
> + __uint(max_entries, 1);
> +} fentry_readings SEC(".maps");
> +
> +/* accumulated readings */
> +struct {
> + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
> + __uint(key_size, sizeof(__u32));
> + __uint(value_size, sizeof(struct bpf_perf_event_value));
> + __uint(max_entries, 1);
> +} accum_readings SEC(".maps");
> +
> +const volatile __u32 num_cpu = 1;
> +
> +SEC("fentry/XXX")
> +int BPF_PROG(fentry_XXX)
> +{
> + __u32 key = bpf_get_smp_processor_id();
> + struct bpf_perf_event_value *ptr;
> + __u32 zero = 0;
> + long err;
> +
> + /* look up before reading, to reduce error */
> + ptr = bpf_map_lookup_elem(&fentry_readings, &zero);
> + if (!ptr)
> + return 0;
> +
> + err = bpf_perf_event_read_value(&events, key, ptr, sizeof(*ptr));
> + if (err)
> + return 0;
> +
> + return 0;
> +}
> +
> +static inline void
> +fexit_update_maps(struct bpf_perf_event_value *after)
> +{
> + struct bpf_perf_event_value *before, diff, *accum;
> + __u32 zero = 0;
> +
> + before = bpf_map_lookup_elem(&fentry_readings, &zero);
> + /* only account samples with a valid fentry_reading */
> + if (before && before->counter) {
> + struct bpf_perf_event_value *accum;
> +
> + diff.counter = after->counter - before->counter;
> + diff.enabled = after->enabled - before->enabled;
> + diff.running = after->running - before->running;
> +
> + accum = bpf_map_lookup_elem(&accum_readings, &zero);
> + if (accum) {
> + accum->counter += diff.counter;
> + accum->enabled += diff.enabled;
> + accum->running += diff.running;
> + }
> + }
> +}
> +
> +SEC("fexit/XXX")
> +int BPF_PROG(fexit_XXX)
> +{
> + struct bpf_perf_event_value reading;
> + __u32 cpu = bpf_get_smp_processor_id();
> + __u32 one = 1, zero = 0;
> + int err;
> +
> + /* read all events before updating the maps, to reduce error */
> + err = bpf_perf_event_read_value(&events, cpu, &reading, sizeof(reading));
> + if (err)
> + return 0;
> +
> + fexit_update_maps(&reading);
> + return 0;
> +}
> +
> +char LICENSE[] SEC("license") = "Dual BSD/GPL";
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index dc0cfa5f26101..7a5ca00496000 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -25,6 +25,7 @@
> #include <stdlib.h>
> #include <perf/evsel.h>
> #include "asm/bug.h"
> +#include "bpf_counter.h"
> #include "callchain.h"
> #include "cgroup.h"
> #include "counts.h"
> @@ -51,6 +52,10 @@
> #include <internal/lib.h>
>
> #include <linux/ctype.h>
> +#include <bpf/bpf.h>
> +#include <bpf/libbpf.h>
> +#include <bpf/btf.h>
> +#include "rlimit.h"
>
> struct perf_missing_features perf_missing_features;
>
> @@ -247,6 +252,7 @@ void evsel__init(struct evsel *evsel,
> evsel->bpf_obj = NULL;
> evsel->bpf_fd = -1;
> INIT_LIST_HEAD(&evsel->config_terms);
> + INIT_LIST_HEAD(&evsel->bpf_counter_list);
> perf_evsel__object.init(evsel);
> evsel->sample_size = __evsel__sample_size(attr->sample_type);
> evsel__calc_id_pos(evsel);
> @@ -1368,6 +1374,7 @@ void evsel__exit(struct evsel *evsel)
> {
> assert(list_empty(&evsel->core.node));
> assert(evsel->evlist == NULL);
> + bpf_counter__destroy(evsel);
> evsel__free_counts(evsel);
> perf_evsel__free_fd(&evsel->core);
> perf_evsel__free_id(&evsel->core);
> @@ -1783,6 +1790,8 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
>
> FD(evsel, cpu, thread) = fd;
>
> + bpf_counter__install_pe(evsel, cpu, fd);
> +
> if (unlikely(test_attr__enabled)) {
> test_attr__open(&evsel->core.attr, pid, cpus->map[cpu],
> fd, group_fd, flags);
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index cd1d8dd431997..8226b1fefa8cf 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -17,6 +17,8 @@ struct cgroup;
> struct perf_counts;
> struct perf_stat_evsel;
> union perf_event;
> +struct bpf_counter_ops;
> +struct target;
>
> typedef int (evsel__sb_cb_t)(union perf_event *event, void *data);
>
> @@ -127,6 +129,8 @@ struct evsel {
> * See also evsel__has_callchain().
> */
> __u64 synth_sample_type;
> + struct list_head bpf_counter_list;
> + struct bpf_counter_ops *bpf_counter_ops;
> };
>
> struct perf_missing_features {
> @@ -424,4 +428,5 @@ static inline bool evsel__is_dummy_event(struct evsel *evsel)
> struct perf_env *evsel__env(struct evsel *evsel);
>
> int evsel__store_ids(struct evsel *evsel, struct evlist *evlist);
> +
> #endif /* __PERF_EVSEL_H */
> diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> index cc5ade85a33fc..278abecb5bdfc 100644
> --- a/tools/perf/util/python.c
> +++ b/tools/perf/util/python.c
> @@ -79,6 +79,27 @@ int metricgroup__copy_metric_events(struct evlist *evlist, struct cgroup *cgrp,
> return 0;
> }
>
> +/*
> + * XXX: All these evsel destructors need some better mechanism, like a linked
> + * list of destructors registered when the relevant code indeed is used instead
> + * of having more and more calls in perf_evsel__delete(). -- acme
> + *
> + * For now, add some more:
> + *
> + * Not to drag the BPF bandwagon...
> + */
> +void bpf_counter__destroy(struct evsel *evsel);
> +int bpf_counter__install_pe(struct evsel *evsel, int cpu, int fd);
> +
> +void bpf_counter__destroy(struct evsel *evsel __maybe_unused)
> +{
> +}
> +
> +int bpf_counter__install_pe(struct evsel *evsel __maybe_unused, int cpu __maybe_unused, int fd __maybe_unused)
> +{
> + return 0;
> +}
> +
> /*
> * Support debug printing even though util/debug.c is not linked. That means
> * implementing 'verbose' and 'eprintf'.
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 583ae4f09c5d1..cce7a76d6473c 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -1045,7 +1045,9 @@ static void print_header(struct perf_stat_config *config,
> if (!config->csv_output) {
> fprintf(output, "\n");
> fprintf(output, " Performance counter stats for ");
> - if (_target->system_wide)
> + if (_target->bpf_str)
> + fprintf(output, "\'BPF program(s) %s", _target->bpf_str);
> + else if (_target->system_wide)
> fprintf(output, "\'system wide");
> else if (_target->cpu_list)
> fprintf(output, "\'CPU(s) %s", _target->cpu_list);
> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> index 8ce1479c98f03..0b3957323f668 100644
> --- a/tools/perf/util/stat.c
> +++ b/tools/perf/util/stat.c
> @@ -527,7 +527,7 @@ int create_perf_stat_counter(struct evsel *evsel,
> if (leader->core.nr_members > 1)
> attr->read_format |= PERF_FORMAT_ID|PERF_FORMAT_GROUP;
>
> - attr->inherit = !config->no_inherit;
> + attr->inherit = !config->no_inherit && list_empty(&evsel->bpf_counter_list);
>
> /*
> * Some events get initialized with sample_(period/type) set,
> diff --git a/tools/perf/util/target.c b/tools/perf/util/target.c
> index a3db13dea937c..0f383418e3df5 100644
> --- a/tools/perf/util/target.c
> +++ b/tools/perf/util/target.c
> @@ -56,6 +56,34 @@ enum target_errno target__validate(struct target *target)
> ret = TARGET_ERRNO__UID_OVERRIDE_SYSTEM;
> }
>
> + /* BPF and CPU are mutually exclusive */
> + if (target->bpf_str && target->cpu_list) {
> + target->cpu_list = NULL;
> + if (ret == TARGET_ERRNO__SUCCESS)
> + ret = TARGET_ERRNO__BPF_OVERRIDE_CPU;
> + }
> +
> + /* BPF and PID/TID are mutually exclusive */
> + if (target->bpf_str && target->tid) {
> + target->tid = NULL;
> + if (ret == TARGET_ERRNO__SUCCESS)
> + ret = TARGET_ERRNO__BPF_OVERRIDE_PID;
> + }
> +
> + /* BPF and UID are mutually exclusive */
> + if (target->bpf_str && target->uid_str) {
> + target->uid_str = NULL;
> + if (ret == TARGET_ERRNO__SUCCESS)
> + ret = TARGET_ERRNO__BPF_OVERRIDE_UID;
> + }
> +
> + /* BPF and THREADS are mutually exclusive */
> + if (target->bpf_str && target->per_thread) {
> + target->per_thread = false;
> + if (ret == TARGET_ERRNO__SUCCESS)
> + ret = TARGET_ERRNO__BPF_OVERRIDE_THREAD;
> + }
> +
> /* THREAD and SYSTEM/CPU are mutually exclusive */
> if (target->per_thread && (target->system_wide || target->cpu_list)) {
> target->per_thread = false;
> @@ -109,6 +137,10 @@ static const char *target__error_str[] = {
> "PID/TID switch overriding SYSTEM",
> "UID switch overriding SYSTEM",
> "SYSTEM/CPU switch overriding PER-THREAD",
> + "BPF switch overriding CPU",
> + "BPF switch overriding PID/TID",
> + "BPF switch overriding UID",
> + "BPF switch overriding THREAD",
> "Invalid User: %s",
> "Problems obtaining information for user %s",
> };
> @@ -134,7 +166,7 @@ int target__strerror(struct target *target, int errnum,
>
> switch (errnum) {
> case TARGET_ERRNO__PID_OVERRIDE_CPU ...
> - TARGET_ERRNO__SYSTEM_OVERRIDE_THREAD:
> + TARGET_ERRNO__BPF_OVERRIDE_THREAD:
> snprintf(buf, buflen, "%s", msg);
> break;
>
> diff --git a/tools/perf/util/target.h b/tools/perf/util/target.h
> index 6ef01a83b24e9..f132c6c2eef81 100644
> --- a/tools/perf/util/target.h
> +++ b/tools/perf/util/target.h
> @@ -10,6 +10,7 @@ struct target {
> const char *tid;
> const char *cpu_list;
> const char *uid_str;
> + const char *bpf_str;
> uid_t uid;
> bool system_wide;
> bool uses_mmap;
> @@ -36,6 +37,10 @@ enum target_errno {
> TARGET_ERRNO__PID_OVERRIDE_SYSTEM,
> TARGET_ERRNO__UID_OVERRIDE_SYSTEM,
> TARGET_ERRNO__SYSTEM_OVERRIDE_THREAD,
> + TARGET_ERRNO__BPF_OVERRIDE_CPU,
> + TARGET_ERRNO__BPF_OVERRIDE_PID,
> + TARGET_ERRNO__BPF_OVERRIDE_UID,
> + TARGET_ERRNO__BPF_OVERRIDE_THREAD,
>
> /* for target__parse_uid() */
> TARGET_ERRNO__INVALID_UID,
> @@ -59,6 +64,11 @@ static inline bool target__has_cpu(struct target *target)
> return target->system_wide || target->cpu_list;
> }
>
> +static inline bool target__has_bpf(struct target *target)
> +{
> + return target->bpf_str;
> +}
> +
> static inline bool target__none(struct target *target)
> {
> return !target__has_task(target) && !target__has_cpu(target);
> --
> 2.24.1
>

--

- Arnaldo