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.

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 <songliubrav...@fb.com>
---
 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

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