git.itanic.dy.fi Git - linux-stable/blob - tools/perf/util/bpf_counter_cgroup.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 /* Copyright (c) 2021 Facebook */
   4 /* Copyright (c) 2021 Google */
   5
   6 #include <assert.h>
   7 #include <limits.h>
   8 #include <unistd.h>
   9 #include <sys/file.h>
  10 #include <sys/time.h>
  11 #include <sys/resource.h>
  12 #include <linux/err.h>
  13 #include <linux/zalloc.h>
  14 #include <linux/perf_event.h>
  15 #include <api/fs/fs.h>
  16 #include <perf/bpf_perf.h>
  17
  18 #include "affinity.h"
  19 #include "bpf_counter.h"
  20 #include "cgroup.h"
  21 #include "counts.h"
  22 #include "debug.h"
  23 #include "evsel.h"
  24 #include "evlist.h"
  25 #include "target.h"
  26 #include "cpumap.h"
  27 #include "thread_map.h"
  28
  29 #include "bpf_skel/bperf_cgroup.skel.h"
  30
  31 static struct perf_event_attr cgrp_switch_attr = {
  32         .type = PERF_TYPE_SOFTWARE,
  33         .config = PERF_COUNT_SW_CGROUP_SWITCHES,
  34         .size = sizeof(cgrp_switch_attr),
  35         .sample_period = 1,
  36         .disabled = 1,
  37 };
  38
  39 static struct evsel *cgrp_switch;
  40 static struct bperf_cgroup_bpf *skel;
  41
  42 #define FD(evt, cpu) (*(int *)xyarray__entry(evt->core.fd, cpu, 0))
  43
  44 static int bperf_load_program(struct evlist *evlist)
  45 {
  46         struct bpf_link *link;
  47         struct evsel *evsel;
  48         struct cgroup *cgrp, *leader_cgrp;
  49         int i, j;
  50         struct perf_cpu cpu;
  51         int total_cpus = cpu__max_cpu().cpu;
  52         int map_size, map_fd;
  53         int prog_fd, err;
  54
  55         skel = bperf_cgroup_bpf__open();
  56         if (!skel) {
  57                 pr_err("Failed to open cgroup skeleton\n");
  58                 return -1;
  59         }
  60
  61         skel->rodata->num_cpus = total_cpus;
  62         skel->rodata->num_events = evlist->core.nr_entries / nr_cgroups;
  63
  64         BUG_ON(evlist->core.nr_entries % nr_cgroups != 0);
  65
  66         /* we need one copy of events per cpu for reading */
  67         map_size = total_cpus * evlist->core.nr_entries / nr_cgroups;
  68         bpf_map__set_max_entries(skel->maps.events, map_size);
  69         bpf_map__set_max_entries(skel->maps.cgrp_idx, nr_cgroups);
  70         /* previous result is saved in a per-cpu array */
  71         map_size = evlist->core.nr_entries / nr_cgroups;
  72         bpf_map__set_max_entries(skel->maps.prev_readings, map_size);
  73         /* cgroup result needs all events (per-cpu) */
  74         map_size = evlist->core.nr_entries;
  75         bpf_map__set_max_entries(skel->maps.cgrp_readings, map_size);
  76
  77         set_max_rlimit();
  78
  79         err = bperf_cgroup_bpf__load(skel);
  80         if (err) {
  81                 pr_err("Failed to load cgroup skeleton\n");
  82                 goto out;
  83         }
  84
  85         if (cgroup_is_v2("perf_event") > 0)
  86                 skel->bss->use_cgroup_v2 = 1;
  87
  88         err = -1;
  89
  90         cgrp_switch = evsel__new(&cgrp_switch_attr);
  91         if (evsel__open_per_cpu(cgrp_switch, evlist->core.all_cpus, -1) < 0) {
  92                 pr_err("Failed to open cgroup switches event\n");
  93                 goto out;
  94         }
  95
  96         perf_cpu_map__for_each_cpu(cpu, i, evlist->core.all_cpus) {
  97                 link = bpf_program__attach_perf_event(skel->progs.on_cgrp_switch,
  98                                                       FD(cgrp_switch, i));
  99                 if (IS_ERR(link)) {
 100                         pr_err("Failed to attach cgroup program\n");
 101                         err = PTR_ERR(link);
 102                         goto out;
 103                 }
 104         }
 105
 106         /*
 107          * Update cgrp_idx map from cgroup-id to event index.
 108          */
 109         cgrp = NULL;
 110         i = 0;
 111
 112         evlist__for_each_entry(evlist, evsel) {
 113                 if (cgrp == NULL || evsel->cgrp == leader_cgrp) {
 114                         leader_cgrp = evsel->cgrp;
 115                         evsel->cgrp = NULL;
 116
 117                         /* open single copy of the events w/o cgroup */
 118                         err = evsel__open_per_cpu(evsel, evlist->core.all_cpus, -1);
 119                         if (err) {
 120                                 pr_err("Failed to open first cgroup events\n");
 121                                 goto out;
 122                         }
 123
 124                         map_fd = bpf_map__fd(skel->maps.events);
 125                         perf_cpu_map__for_each_cpu(cpu, j, evlist->core.all_cpus) {
 126                                 int fd = FD(evsel, j);
 127                                 __u32 idx = evsel->core.idx * total_cpus + cpu.cpu;
 128
 129                                 err = bpf_map_update_elem(map_fd, &idx, &fd,
 130                                                           BPF_ANY);
 131                                 if (err < 0) {
 132                                         pr_err("Failed to update perf_event fd\n");
 133                                         goto out;
 134                                 }
 135                         }
 136
 137                         evsel->cgrp = leader_cgrp;
 138                 }
 139                 evsel->supported = true;
 140
 141                 if (evsel->cgrp == cgrp)
 142                         continue;
 143
 144                 cgrp = evsel->cgrp;
 145
 146                 if (read_cgroup_id(cgrp) < 0) {
 147                         pr_err("Failed to get cgroup id\n");
 148                         err = -1;
 149                         goto out;
 150                 }
 151
 152                 map_fd = bpf_map__fd(skel->maps.cgrp_idx);
 153                 err = bpf_map_update_elem(map_fd, &cgrp->id, &i, BPF_ANY);
 154                 if (err < 0) {
 155                         pr_err("Failed to update cgroup index map\n");
 156                         goto out;
 157                 }
 158
 159                 i++;
 160         }
 161
 162         /*
 163          * bperf uses BPF_PROG_TEST_RUN to get accurate reading. Check
 164          * whether the kernel support it
 165          */
 166         prog_fd = bpf_program__fd(skel->progs.trigger_read);
 167         err = bperf_trigger_reading(prog_fd, 0);
 168         if (err) {
 169                 pr_warning("The kernel does not support test_run for raw_tp BPF programs.\n"
 170                            "Therefore, --for-each-cgroup might show inaccurate readings\n");
 171                 err = 0;
 172         }
 173
 174 out:
 175         return err;
 176 }
 177
 178 static int bperf_cgrp__load(struct evsel *evsel,
 179                             struct target *target __maybe_unused)
 180 {
 181         static bool bperf_loaded = false;
 182
 183         evsel->bperf_leader_prog_fd = -1;
 184         evsel->bperf_leader_link_fd = -1;
 185
 186         if (!bperf_loaded && bperf_load_program(evsel->evlist))
 187                 return -1;
 188
 189         bperf_loaded = true;
 190         /* just to bypass bpf_counter_skip() */
 191         evsel->follower_skel = (struct bperf_follower_bpf *)skel;
 192
 193         return 0;
 194 }
 195
 196 static int bperf_cgrp__install_pe(struct evsel *evsel __maybe_unused,
 197                                   int cpu __maybe_unused, int fd __maybe_unused)
 198 {
 199         /* nothing to do */
 200         return 0;
 201 }
 202
 203 /*
 204  * trigger the leader prog on each cpu, so the cgrp_reading map could get
 205  * the latest results.
 206  */
 207 static int bperf_cgrp__sync_counters(struct evlist *evlist)
 208 {
 209         struct perf_cpu cpu;
 210         int idx;
 211         int prog_fd = bpf_program__fd(skel->progs.trigger_read);
 212
 213         perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.all_cpus)
 214                 bperf_trigger_reading(prog_fd, cpu.cpu);
 215
 216         return 0;
 217 }
 218
 219 static int bperf_cgrp__enable(struct evsel *evsel)
 220 {
 221         if (evsel->core.idx)
 222                 return 0;
 223
 224         bperf_cgrp__sync_counters(evsel->evlist);
 225
 226         skel->bss->enabled = 1;
 227         return 0;
 228 }
 229
 230 static int bperf_cgrp__disable(struct evsel *evsel)
 231 {
 232         if (evsel->core.idx)
 233                 return 0;
 234
 235         bperf_cgrp__sync_counters(evsel->evlist);
 236
 237         skel->bss->enabled = 0;
 238         return 0;
 239 }
 240
 241 static int bperf_cgrp__read(struct evsel *evsel)
 242 {
 243         struct evlist *evlist = evsel->evlist;
 244         int total_cpus = cpu__max_cpu().cpu;
 245         struct perf_counts_values *counts;
 246         struct bpf_perf_event_value *values;
 247         int reading_map_fd, err = 0;
 248
 249         if (evsel->core.idx)
 250                 return 0;
 251
 252         bperf_cgrp__sync_counters(evsel->evlist);
 253
 254         values = calloc(total_cpus, sizeof(*values));
 255         if (values == NULL)
 256                 return -ENOMEM;
 257
 258         reading_map_fd = bpf_map__fd(skel->maps.cgrp_readings);
 259
 260         evlist__for_each_entry(evlist, evsel) {
 261                 __u32 idx = evsel->core.idx;
 262                 int i;
 263                 struct perf_cpu cpu;
 264
 265                 err = bpf_map_lookup_elem(reading_map_fd, &idx, values);
 266                 if (err) {
 267                         pr_err("bpf map lookup failed: idx=%u, event=%s, cgrp=%s\n",
 268                                idx, evsel__name(evsel), evsel->cgrp->name);
 269                         goto out;
 270                 }
 271
 272                 perf_cpu_map__for_each_cpu(cpu, i, evlist->core.all_cpus) {
 273                         counts = perf_counts(evsel->counts, i, 0);
 274                         counts->val = values[cpu.cpu].counter;
 275                         counts->ena = values[cpu.cpu].enabled;
 276                         counts->run = values[cpu.cpu].running;
 277                 }
 278         }
 279
 280 out:
 281         free(values);
 282         return err;
 283 }
 284
 285 static int bperf_cgrp__destroy(struct evsel *evsel)
 286 {
 287         if (evsel->core.idx)
 288                 return 0;
 289
 290         bperf_cgroup_bpf__destroy(skel);
 291         evsel__delete(cgrp_switch);  // it'll destroy on_switch progs too
 292
 293         return 0;
 294 }
 295
 296 struct bpf_counter_ops bperf_cgrp_ops = {
 297         .load       = bperf_cgrp__load,
 298         .enable     = bperf_cgrp__enable,
 299         .disable    = bperf_cgrp__disable,
 300         .read       = bperf_cgrp__read,
 301         .install_pe = bperf_cgrp__install_pe,
 302         .destroy    = bperf_cgrp__destroy,
 303 };