1 files changed, 295 insertions, 0 deletions
diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c
new file mode 100644
index 000000000..1c82377ed
--- /dev/null
+++ b/tools/perf/util/bpf_counter_cgroup.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Copyright (c) 2021 Facebook */
+/* Copyright (c) 2021 Google */
+
+#include <assert.h>
+#include <limits.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <linux/err.h>
+#include <linux/zalloc.h>
+#include <linux/perf_event.h>
+#include <api/fs/fs.h>
+#include <perf/bpf_perf.h>
+
+#include "affinity.h"
+#include "bpf_counter.h"
+#include "cgroup.h"
+#include "counts.h"
+#include "debug.h"
+#include "evsel.h"
+#include "evlist.h"
+#include "target.h"
+#include "cpumap.h"
+#include "thread_map.h"
+
+#include "bpf_skel/bperf_cgroup.skel.h"
+
+static struct perf_event_attr cgrp_switch_attr = {
+	.type = PERF_TYPE_SOFTWARE,
+	.config = PERF_COUNT_SW_CGROUP_SWITCHES,
+	.size = sizeof(cgrp_switch_attr),
+	.sample_period = 1,
+	.disabled = 1,
+};
+
+static struct evsel *cgrp_switch;
+static struct bperf_cgroup_bpf *skel;
+
+#define FD(evt, cpu) (*(int *)xyarray__entry(evt->core.fd, cpu, 0))
+
+static int bperf_load_program(struct evlist *evlist)
+{
+	struct bpf_link *link;
+	struct evsel *evsel;
+	struct cgroup *cgrp, *leader_cgrp;
+	int i, j;
+	struct perf_cpu cpu;
+	int total_cpus = cpu__max_cpu().cpu;
+	int map_size, map_fd;
+	int prog_fd, err;
+
+	skel = bperf_cgroup_bpf__open();
+	if (!skel) {
+		pr_err("Failed to open cgroup skeleton\n");
+		return -1;
+	}
+
+	skel->rodata->num_cpus = total_cpus;
+	skel->rodata->num_events = evlist->core.nr_entries / nr_cgroups;
+
+	BUG_ON(evlist->core.nr_entries % nr_cgroups != 0);
+
+	/* we need one copy of events per cpu for reading */
+	map_size = total_cpus * evlist->core.nr_entries / nr_cgroups;
+	bpf_map__set_max_entries(skel->maps.events, map_size);
+	bpf_map__set_max_entries(skel->maps.cgrp_idx, nr_cgroups);
+	/* previous result is saved in a per-cpu array */
+	map_size = evlist->core.nr_entries / nr_cgroups;
+	bpf_map__set_max_entries(skel->maps.prev_readings, map_size);
+	/* cgroup result needs all events (per-cpu) */
+	map_size = evlist->core.nr_entries;
+	bpf_map__set_max_entries(skel->maps.cgrp_readings, map_size);
+
+	set_max_rlimit();
+
+	err = bperf_cgroup_bpf__load(skel);
+	if (err) {
+		pr_err("Failed to load cgroup skeleton\n");
+		goto out;
+	}
+
+	if (cgroup_is_v2("perf_event") > 0)
+		skel->bss->use_cgroup_v2 = 1;
+
+	err = -1;
+
+	cgrp_switch = evsel__new(&cgrp_switch_attr);
+	if (evsel__open_per_cpu(cgrp_switch, evlist->core.all_cpus, -1) < 0) {
+		pr_err("Failed to open cgroup switches event\n");
+		goto out;
+	}
+
+	perf_cpu_map__for_each_cpu(cpu, i, evlist->core.all_cpus) {
+		link = bpf_program__attach_perf_event(skel->progs.on_cgrp_switch,
+						      FD(cgrp_switch, i));
+		if (IS_ERR(link)) {
+			pr_err("Failed to attach cgroup program\n");
+			err = PTR_ERR(link);
+			goto out;
+		}
+	}
+
+	/*
+	 * Update cgrp_idx map from cgroup-id to event index.
+	 */
+	cgrp = NULL;
+	i = 0;
+
+	evlist__for_each_entry(evlist, evsel) {
+		if (cgrp == NULL || evsel->cgrp == leader_cgrp) {
+			leader_cgrp = evsel->cgrp;
+			evsel->cgrp = NULL;
+
+			/* open single copy of the events w/o cgroup */
+			err = evsel__open_per_cpu(evsel, evsel->core.cpus, -1);
+			if (err == 0)
+				evsel->supported = true;
+
+			map_fd = bpf_map__fd(skel->maps.events);
+			perf_cpu_map__for_each_cpu(cpu, j, evsel->core.cpus) {
+				int fd = FD(evsel, j);
+				__u32 idx = evsel->core.idx * total_cpus + cpu.cpu;
+
+				bpf_map_update_elem(map_fd, &idx, &fd, BPF_ANY);
+			}
+
+			evsel->cgrp = leader_cgrp;
+		}
+
+		if (evsel->cgrp == cgrp)
+			continue;
+
+		cgrp = evsel->cgrp;
+
+		if (read_cgroup_id(cgrp) < 0) {
+			pr_err("Failed to get cgroup id\n");
+			err = -1;
+			goto out;
+		}
+
+		map_fd = bpf_map__fd(skel->maps.cgrp_idx);
+		err = bpf_map_update_elem(map_fd, &cgrp->id, &i, BPF_ANY);
+		if (err < 0) {
+			pr_err("Failed to update cgroup index map\n");
+			goto out;
+		}
+
+		i++;
+	}
+
+	/*
+	 * bperf uses BPF_PROG_TEST_RUN to get accurate reading. Check
+	 * whether the kernel support it
+	 */
+	prog_fd = bpf_program__fd(skel->progs.trigger_read);
+	err = bperf_trigger_reading(prog_fd, 0);
+	if (err) {
+		pr_warning("The kernel does not support test_run for raw_tp BPF programs.\n"
+			   "Therefore, --for-each-cgroup might show inaccurate readings\n");
+		err = 0;
+	}
+
+out:
+	return err;
+}
+
+static int bperf_cgrp__load(struct evsel *evsel,
+			    struct target *target __maybe_unused)
+{
+	static bool bperf_loaded = false;
+
+	evsel->bperf_leader_prog_fd = -1;
+	evsel->bperf_leader_link_fd = -1;
+
+	if (!bperf_loaded && bperf_load_program(evsel->evlist))
+		return -1;
+
+	bperf_loaded = true;
+	/* just to bypass bpf_counter_skip() */
+	evsel->follower_skel = (struct bperf_follower_bpf *)skel;
+
+	return 0;
+}
+
+static int bperf_cgrp__install_pe(struct evsel *evsel __maybe_unused,
+				  int cpu __maybe_unused, int fd __maybe_unused)
+{
+	/* nothing to do */
+	return 0;
+}
+
+/*
+ * trigger the leader prog on each cpu, so the cgrp_reading map could get
+ * the latest results.
+ */
+static int bperf_cgrp__sync_counters(struct evlist *evlist)
+{
+	struct perf_cpu cpu;
+	int idx;
+	int prog_fd = bpf_program__fd(skel->progs.trigger_read);
+
+	perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.all_cpus)
+		bperf_trigger_reading(prog_fd, cpu.cpu);
+
+	return 0;
+}
+
+static int bperf_cgrp__enable(struct evsel *evsel)
+{
+	if (evsel->core.idx)
+		return 0;
+
+	bperf_cgrp__sync_counters(evsel->evlist);
+
+	skel->bss->enabled = 1;
+	return 0;
+}
+
+static int bperf_cgrp__disable(struct evsel *evsel)
+{
+	if (evsel->core.idx)
+		return 0;
+
+	bperf_cgrp__sync_counters(evsel->evlist);
+
+	skel->bss->enabled = 0;
+	return 0;
+}
+
+static int bperf_cgrp__read(struct evsel *evsel)
+{
+	struct evlist *evlist = evsel->evlist;
+	int total_cpus = cpu__max_cpu().cpu;
+	struct perf_counts_values *counts;
+	struct bpf_perf_event_value *values;
+	int reading_map_fd, err = 0;
+
+	if (evsel->core.idx)
+		return 0;
+
+	bperf_cgrp__sync_counters(evsel->evlist);
+
+	values = calloc(total_cpus, sizeof(*values));
+	if (values == NULL)
+		return -ENOMEM;
+
+	reading_map_fd = bpf_map__fd(skel->maps.cgrp_readings);
+
+	evlist__for_each_entry(evlist, evsel) {
+		__u32 idx = evsel->core.idx;
+		int i;
+		struct perf_cpu cpu;
+
+		err = bpf_map_lookup_elem(reading_map_fd, &idx, values);
+		if (err) {
+			pr_err("bpf map lookup failed: idx=%u, event=%s, cgrp=%s\n",
+			       idx, evsel__name(evsel), evsel->cgrp->name);
+			goto out;
+		}
+
+		perf_cpu_map__for_each_cpu(cpu, i, evsel->core.cpus) {
+			counts = perf_counts(evsel->counts, i, 0);
+			counts->val = values[cpu.cpu].counter;
+			counts->ena = values[cpu.cpu].enabled;
+			counts->run = values[cpu.cpu].running;
+		}
+	}
+
+out:
+	free(values);
+	return err;
+}
+
+static int bperf_cgrp__destroy(struct evsel *evsel)
+{
+	if (evsel->core.idx)
+		return 0;
+
+	bperf_cgroup_bpf__destroy(skel);
+	evsel__delete(cgrp_switch);  // it'll destroy on_switch progs too
+
+	return 0;
+}
+
+struct bpf_counter_ops bperf_cgrp_ops = {
+	.load       = bperf_cgrp__load,
+	.enable     = bperf_cgrp__enable,
+	.disable    = bperf_cgrp__disable,
+	.read       = bperf_cgrp__read,
+	.install_pe = bperf_cgrp__install_pe,
+	.destroy    = bperf_cgrp__destroy,
+};