diff options
Diffstat (limited to 'tools/perf/util/bpf_counter.c')
| -rw-r--r-- | tools/perf/util/bpf_counter.c | 837 |
1 files changed, 837 insertions, 0 deletions
diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c new file mode 100644 index 000000000000..ef1c15e4aeba --- /dev/null +++ b/tools/perf/util/bpf_counter.c @@ -0,0 +1,837 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* Copyright (c) 2019 Facebook */ + +#include <assert.h> +#include <limits.h> +#include <unistd.h> +#include <sys/file.h> +#include <sys/time.h> +#include <linux/err.h> +#include <linux/zalloc.h> +#include <api/fs/fs.h> +#include <perf/bpf_perf.h> + +#include "bpf_counter.h" +#include "bpf-utils.h" +#include "counts.h" +#include "debug.h" +#include "evsel.h" +#include "evlist.h" +#include "target.h" +#include "cgroup.h" +#include "cpumap.h" +#include "thread_map.h" + +#include "bpf_skel/bpf_prog_profiler.skel.h" +#include "bpf_skel/bperf_u.h" +#include "bpf_skel/bperf_leader.skel.h" +#include "bpf_skel/bperf_follower.skel.h" + +#define ATTR_MAP_SIZE 16 + +static inline void *u64_to_ptr(__u64 ptr) +{ + return (void *)(unsigned long)ptr; +} + +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_func_info *func_info; + struct perf_bpil *info_linear; + const struct btf_type *t; + struct btf *btf = NULL; + char *name = NULL; + + info_linear = get_bpf_prog_info_linear(tgt_fd, 1UL << PERF_BPIL_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) { + pr_debug("prog FD %d doesn't have valid btf\n", tgt_fd); + goto out; + } + + btf = btf__load_from_kernel_by_id(info_linear->info.btf_id); + if (libbpf_get_error(btf)) { + pr_debug("failed to load btf for prog FD %d\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: + btf__free(btf); + 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__set_max_entries(skel->maps.events, evsel__nr_cpus(evsel)); + bpf_map__set_max_entries(skel->maps.fentry_readings, 1); + bpf_map__set_max_entries(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__disable(struct evsel *evsel) +{ + struct bpf_counter *counter; + + list_for_each_entry(counter, &evsel->bpf_counter_list, list) { + assert(counter->skel != NULL); + bpf_prog_profiler_bpf__detach(counter->skel); + } + return 0; +} + +static int bpf_program_profiler__read(struct evsel *evsel) +{ + // BPF_MAP_TYPE_PERCPU_ARRAY uses /sys/devices/system/cpu/possible + // Sometimes possible > online, like on a Ryzen 3900X that has 24 + // threads but its possible showed 0-31 -acme + int num_cpu_bpf = libbpf_num_possible_cpus(); + struct bpf_perf_event_value values[num_cpu_bpf]; + struct bpf_counter *counter; + struct perf_counts_values *counts; + int reading_map_fd; + __u32 key = 0; + int err, idx, bpf_cpu; + + if (list_empty(&evsel->bpf_counter_list)) + return -EAGAIN; + + perf_cpu_map__for_each_idx(idx, evsel__cpus(evsel)) { + counts = perf_counts(evsel->counts, idx, 0); + counts->val = 0; + counts->ena = 0; + counts->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 (bpf_cpu = 0; bpf_cpu < num_cpu_bpf; bpf_cpu++) { + idx = perf_cpu_map__idx(evsel__cpus(evsel), + (struct perf_cpu){.cpu = bpf_cpu}); + if (idx == -1) + continue; + counts = perf_counts(evsel->counts, idx, 0); + counts->val += values[bpf_cpu].counter; + counts->ena += values[bpf_cpu].enabled; + counts->run += values[bpf_cpu].running; + } + } + return 0; +} + +static int bpf_program_profiler__install_pe(struct evsel *evsel, int cpu_map_idx, + 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_map_idx, &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, + .disable = bpf_program_profiler__disable, + .read = bpf_program_profiler__read, + .destroy = bpf_program_profiler__destroy, + .install_pe = bpf_program_profiler__install_pe, +}; + +static bool bperf_attr_map_compatible(int attr_map_fd) +{ + struct bpf_map_info map_info = {0}; + __u32 map_info_len = sizeof(map_info); + int err; + + err = bpf_obj_get_info_by_fd(attr_map_fd, &map_info, &map_info_len); + + if (err) + return false; + return (map_info.key_size == sizeof(struct perf_event_attr)) && + (map_info.value_size == sizeof(struct perf_event_attr_map_entry)); +} + +#ifndef HAVE_LIBBPF_BPF_MAP_CREATE +LIBBPF_API int bpf_create_map(enum bpf_map_type map_type, int key_size, + int value_size, int max_entries, __u32 map_flags); +int +bpf_map_create(enum bpf_map_type map_type, + const char *map_name __maybe_unused, + __u32 key_size, + __u32 value_size, + __u32 max_entries, + const struct bpf_map_create_opts *opts __maybe_unused) +{ +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wdeprecated-declarations" + return bpf_create_map(map_type, key_size, value_size, max_entries, 0); +#pragma GCC diagnostic pop +} +#endif + +static int bperf_lock_attr_map(struct target *target) +{ + char path[PATH_MAX]; + int map_fd, err; + + if (target->attr_map) { + scnprintf(path, PATH_MAX, "%s", target->attr_map); + } else { + scnprintf(path, PATH_MAX, "%s/fs/bpf/%s", sysfs__mountpoint(), + BPF_PERF_DEFAULT_ATTR_MAP_PATH); + } + + if (access(path, F_OK)) { + map_fd = bpf_map_create(BPF_MAP_TYPE_HASH, NULL, + sizeof(struct perf_event_attr), + sizeof(struct perf_event_attr_map_entry), + ATTR_MAP_SIZE, NULL); + if (map_fd < 0) + return -1; + + err = bpf_obj_pin(map_fd, path); + if (err) { + /* someone pinned the map in parallel? */ + close(map_fd); + map_fd = bpf_obj_get(path); + if (map_fd < 0) + return -1; + } + } else { + map_fd = bpf_obj_get(path); + if (map_fd < 0) + return -1; + } + + if (!bperf_attr_map_compatible(map_fd)) { + close(map_fd); + return -1; + + } + err = flock(map_fd, LOCK_EX); + if (err) { + close(map_fd); + return -1; + } + return map_fd; +} + +static int bperf_check_target(struct evsel *evsel, + struct target *target, + enum bperf_filter_type *filter_type, + __u32 *filter_entry_cnt) +{ + if (evsel->core.leader->nr_members > 1) { + pr_err("bpf managed perf events do not yet support groups.\n"); + return -1; + } + + /* determine filter type based on target */ + if (target->system_wide) { + *filter_type = BPERF_FILTER_GLOBAL; + *filter_entry_cnt = 1; + } else if (target->cpu_list) { + *filter_type = BPERF_FILTER_CPU; + *filter_entry_cnt = perf_cpu_map__nr(evsel__cpus(evsel)); + } else if (target->tid) { + *filter_type = BPERF_FILTER_PID; + *filter_entry_cnt = perf_thread_map__nr(evsel->core.threads); + } else if (target->pid || evsel->evlist->workload.pid != -1) { + *filter_type = BPERF_FILTER_TGID; + *filter_entry_cnt = perf_thread_map__nr(evsel->core.threads); + } else { + pr_err("bpf managed perf events do not yet support these targets.\n"); + return -1; + } + + return 0; +} + +static struct perf_cpu_map *all_cpu_map; + +static int bperf_reload_leader_program(struct evsel *evsel, int attr_map_fd, + struct perf_event_attr_map_entry *entry) +{ + struct bperf_leader_bpf *skel = bperf_leader_bpf__open(); + int link_fd, diff_map_fd, err; + struct bpf_link *link = NULL; + + if (!skel) { + pr_err("Failed to open leader skeleton\n"); + return -1; + } + + bpf_map__set_max_entries(skel->maps.events, libbpf_num_possible_cpus()); + err = bperf_leader_bpf__load(skel); + if (err) { + pr_err("Failed to load leader skeleton\n"); + goto out; + } + + link = bpf_program__attach(skel->progs.on_switch); + if (IS_ERR(link)) { + pr_err("Failed to attach leader program\n"); + err = PTR_ERR(link); + goto out; + } + + link_fd = bpf_link__fd(link); + diff_map_fd = bpf_map__fd(skel->maps.diff_readings); + entry->link_id = bpf_link_get_id(link_fd); + entry->diff_map_id = bpf_map_get_id(diff_map_fd); + err = bpf_map_update_elem(attr_map_fd, &evsel->core.attr, entry, BPF_ANY); + assert(err == 0); + + evsel->bperf_leader_link_fd = bpf_link_get_fd_by_id(entry->link_id); + assert(evsel->bperf_leader_link_fd >= 0); + + /* + * save leader_skel for install_pe, which is called within + * following evsel__open_per_cpu call + */ + evsel->leader_skel = skel; + evsel__open_per_cpu(evsel, all_cpu_map, -1); + +out: + bperf_leader_bpf__destroy(skel); + bpf_link__destroy(link); + return err; +} + +static int bperf__load(struct evsel *evsel, struct target *target) +{ + struct perf_event_attr_map_entry entry = {0xffffffff, 0xffffffff}; + int attr_map_fd, diff_map_fd = -1, err; + enum bperf_filter_type filter_type; + __u32 filter_entry_cnt, i; + + if (bperf_check_target(evsel, target, &filter_type, &filter_entry_cnt)) + return -1; + + if (!all_cpu_map) { + all_cpu_map = perf_cpu_map__new(NULL); + if (!all_cpu_map) + return -1; + } + + evsel->bperf_leader_prog_fd = -1; + evsel->bperf_leader_link_fd = -1; + + /* + * Step 1: hold a fd on the leader program and the bpf_link, if + * the program is not already gone, reload the program. + * Use flock() to ensure exclusive access to the perf_event_attr + * map. + */ + attr_map_fd = bperf_lock_attr_map(target); + if (attr_map_fd < 0) { + pr_err("Failed to lock perf_event_attr map\n"); + return -1; + } + + err = bpf_map_lookup_elem(attr_map_fd, &evsel->core.attr, &entry); + if (err) { + err = bpf_map_update_elem(attr_map_fd, &evsel->core.attr, &entry, BPF_ANY); + if (err) + goto out; + } + + evsel->bperf_leader_link_fd = bpf_link_get_fd_by_id(entry.link_id); + if (evsel->bperf_leader_link_fd < 0 && + bperf_reload_leader_program(evsel, attr_map_fd, &entry)) { + err = -1; + goto out; + } + /* + * The bpf_link holds reference to the leader program, and the + * leader program holds reference to the maps. Therefore, if + * link_id is valid, diff_map_id should also be valid. + */ + evsel->bperf_leader_prog_fd = bpf_prog_get_fd_by_id( + bpf_link_get_prog_id(evsel->bperf_leader_link_fd)); + assert(evsel->bperf_leader_prog_fd >= 0); + + diff_map_fd = bpf_map_get_fd_by_id(entry.diff_map_id); + assert(diff_map_fd >= 0); + + /* + * bperf uses BPF_PROG_TEST_RUN to get accurate reading. Check + * whether the kernel support it + */ + err = bperf_trigger_reading(evsel->bperf_leader_prog_fd, 0); + if (err) { + pr_err("The kernel does not support test_run for raw_tp BPF programs.\n" + "Therefore, --use-bpf might show inaccurate readings\n"); + goto out; + } + + /* Step 2: load the follower skeleton */ + evsel->follower_skel = bperf_follower_bpf__open(); + if (!evsel->follower_skel) { + err = -1; + pr_err("Failed to open follower skeleton\n"); + goto out; + } + + /* attach fexit program to the leader program */ + bpf_program__set_attach_target(evsel->follower_skel->progs.fexit_XXX, + evsel->bperf_leader_prog_fd, "on_switch"); + + /* connect to leader diff_reading map */ + bpf_map__reuse_fd(evsel->follower_skel->maps.diff_readings, diff_map_fd); + + /* set up reading map */ + bpf_map__set_max_entries(evsel->follower_skel->maps.accum_readings, + filter_entry_cnt); + /* set up follower filter based on target */ + bpf_map__set_max_entries(evsel->follower_skel->maps.filter, + filter_entry_cnt); + err = bperf_follower_bpf__load(evsel->follower_skel); + if (err) { + pr_err("Failed to load follower skeleton\n"); + bperf_follower_bpf__destroy(evsel->follower_skel); + evsel->follower_skel = NULL; + goto out; + } + + for (i = 0; i < filter_entry_cnt; i++) { + int filter_map_fd; + __u32 key; + + if (filter_type == BPERF_FILTER_PID || + filter_type == BPERF_FILTER_TGID) + key = evsel->core.threads->map[i].pid; + else if (filter_type == BPERF_FILTER_CPU) + key = evsel->core.cpus->map[i].cpu; + else + break; + + filter_map_fd = bpf_map__fd(evsel->follower_skel->maps.filter); + bpf_map_update_elem(filter_map_fd, &key, &i, BPF_ANY); + } + + evsel->follower_skel->bss->type = filter_type; + + err = bperf_follower_bpf__attach(evsel->follower_skel); + +out: + if (err && evsel->bperf_leader_link_fd >= 0) + close(evsel->bperf_leader_link_fd); + if (err && evsel->bperf_leader_prog_fd >= 0) + close(evsel->bperf_leader_prog_fd); + if (diff_map_fd >= 0) + close(diff_map_fd); + + flock(attr_map_fd, LOCK_UN); + close(attr_map_fd); + + return err; +} + +static int bperf__install_pe(struct evsel *evsel, int cpu_map_idx, int fd) +{ + struct bperf_leader_bpf *skel = evsel->leader_skel; + + return bpf_map_update_elem(bpf_map__fd(skel->maps.events), + &cpu_map_idx, &fd, BPF_ANY); +} + +/* + * trigger the leader prog on each cpu, so the accum_reading map could get + * the latest readings. + */ +static int bperf_sync_counters(struct evsel *evsel) +{ + int num_cpu, i, cpu; + + num_cpu = all_cpu_map->nr; + for (i = 0; i < num_cpu; i++) { + cpu = all_cpu_map->map[i].cpu; + bperf_trigger_reading(evsel->bperf_leader_prog_fd, cpu); + } + return 0; +} + +static int bperf__enable(struct evsel *evsel) +{ + evsel->follower_skel->bss->enabled = 1; + return 0; +} + +static int bperf__disable(struct evsel *evsel) +{ + evsel->follower_skel->bss->enabled = 0; + return 0; +} + +static int bperf__read(struct evsel *evsel) +{ + struct bperf_follower_bpf *skel = evsel->follower_skel; + __u32 num_cpu_bpf = cpu__max_cpu().cpu; + struct bpf_perf_event_value values[num_cpu_bpf]; + struct perf_counts_values *counts; + int reading_map_fd, err = 0; + __u32 i; + int j; + + bperf_sync_counters(evsel); + reading_map_fd = bpf_map__fd(skel->maps.accum_readings); + + for (i = 0; i < bpf_map__max_entries(skel->maps.accum_readings); i++) { + struct perf_cpu entry; + __u32 cpu; + + err = bpf_map_lookup_elem(reading_map_fd, &i, values); + if (err) + goto out; + switch (evsel->follower_skel->bss->type) { + case BPERF_FILTER_GLOBAL: + assert(i == 0); + + perf_cpu_map__for_each_cpu(entry, j, evsel__cpus(evsel)) { + counts = perf_counts(evsel->counts, j, 0); + counts->val = values[entry.cpu].counter; + counts->ena = values[entry.cpu].enabled; + counts->run = values[entry.cpu].running; + } + break; + case BPERF_FILTER_CPU: + cpu = perf_cpu_map__cpu(evsel__cpus(evsel), i).cpu; + assert(cpu >= 0); + counts = perf_counts(evsel->counts, i, 0); + counts->val = values[cpu].counter; + counts->ena = values[cpu].enabled; + counts->run = values[cpu].running; + break; + case BPERF_FILTER_PID: + case BPERF_FILTER_TGID: + counts = perf_counts(evsel->counts, 0, i); + counts->val = 0; + counts->ena = 0; + counts->run = 0; + + for (cpu = 0; cpu < num_cpu_bpf; cpu++) { + counts->val += values[cpu].counter; + counts->ena += values[cpu].enabled; + counts->run += values[cpu].running; + } + break; + default: + break; + } + } +out: + return err; +} + +static int bperf__destroy(struct evsel *evsel) +{ + bperf_follower_bpf__destroy(evsel->follower_skel); + close(evsel->bperf_leader_prog_fd); + close(evsel->bperf_leader_link_fd); + return 0; +} + +/* + * bperf: share hardware PMCs with BPF + * + * perf uses performance monitoring counters (PMC) to monitor system + * performance. The PMCs are limited hardware resources. For example, + * Intel CPUs have 3x fixed PMCs and 4x programmable PMCs per cpu. + * + * Modern data center systems use these PMCs in many different ways: + * system level monitoring, (maybe nested) container level monitoring, per + * process monitoring, profiling (in sample mode), etc. In some cases, + * there are more active perf_events than available hardware PMCs. To allow + * all perf_events to have a chance to run, it is necessary to do expensive + * time multiplexing of events. + * + * On the other hand, many monitoring tools count the common metrics + * (cycles, instructions). It is a waste to have multiple tools create + * multiple perf_events of "cycles" and occupy multiple PMCs. + * + * bperf tries to reduce such wastes by allowing multiple perf_events of + * "cycles" or "instructions" (at different scopes) to share PMUs. Instead + * of having each perf-stat session to read its own perf_events, bperf uses + * BPF programs to read the perf_events and aggregate readings to BPF maps. + * Then, the perf-stat session(s) reads the values from these BPF maps. + * + * || + * shared progs and maps <- || -> per session progs and maps + * || + * --------------- || + * | perf_events | || + * --------------- fexit || ----------------- + * | --------||----> | follower prog | + * --------------- / || --- ----------------- + * cs -> | leader prog |/ ||/ | | + * --> --------------- /|| -------------- ------------------ + * / | | / || | filter map | | accum_readings | + * / ------------ ------------ || -------------- ------------------ + * | | prev map | | diff map | || | + * | ------------ ------------ || | + * \ || | + * = \ ==================================================== | ============ + * \ / user space + * \ / + * \ / + * BPF_PROG_TEST_RUN BPF_MAP_LOOKUP_ELEM + * \ / + * \ / + * \------ perf-stat ----------------------/ + * + * The figure above shows the architecture of bperf. Note that the figure + * is divided into 3 regions: shared progs and maps (top left), per session + * progs and maps (top right), and user space (bottom). + * + * The leader prog is triggered on each context switch (cs). The leader + * prog reads perf_events and stores the difference (current_reading - + * previous_reading) to the diff map. For the same metric, e.g. "cycles", + * multiple perf-stat sessions share the same leader prog. + * + * Each perf-stat session creates a follower prog as fexit program to the + * leader prog. It is possible to attach up to BPF_MAX_TRAMP_PROGS (38) + * follower progs to the same leader prog. The follower prog checks current + * task and processor ID to decide whether to add the value from the diff + * map to its accumulated reading map (accum_readings). + * + * Finally, perf-stat user space reads the value from accum_reading map. + * + * Besides context switch, it is also necessary to trigger the leader prog + * before perf-stat reads the value. Otherwise, the accum_reading map may + * not have the latest reading from the perf_events. This is achieved by + * triggering the event via sys_bpf(BPF_PROG_TEST_RUN) to each CPU. + * + * Comment before the definition of struct perf_event_attr_map_entry + * describes how different sessions of perf-stat share information about + * the leader prog. + */ + +struct bpf_counter_ops bperf_ops = { + .load = bperf__load, + .enable = bperf__enable, + .disable = bperf__disable, + .read = bperf__read, + .install_pe = bperf__install_pe, + .destroy = bperf__destroy, +}; + +extern struct bpf_counter_ops bperf_cgrp_ops; + +static inline bool bpf_counter_skip(struct evsel *evsel) +{ + return list_empty(&evsel->bpf_counter_list) && + evsel->follower_skel == NULL; +} + +int bpf_counter__install_pe(struct evsel *evsel, int cpu_map_idx, int fd) +{ + if (bpf_counter_skip(evsel)) + return 0; + return evsel->bpf_counter_ops->install_pe(evsel, cpu_map_idx, fd); +} + +int bpf_counter__load(struct evsel *evsel, struct target *target) +{ + if (target->bpf_str) + evsel->bpf_counter_ops = &bpf_program_profiler_ops; + else if (cgrp_event_expanded && target->use_bpf) + evsel->bpf_counter_ops = &bperf_cgrp_ops; + else if (target->use_bpf || evsel->bpf_counter || + evsel__match_bpf_counter_events(evsel->name)) + evsel->bpf_counter_ops = &bperf_ops; + + if (evsel->bpf_counter_ops) + return evsel->bpf_counter_ops->load(evsel, target); + return 0; +} + +int bpf_counter__enable(struct evsel *evsel) +{ + if (bpf_counter_skip(evsel)) + return 0; + return evsel->bpf_counter_ops->enable(evsel); +} + +int bpf_counter__disable(struct evsel *evsel) +{ + if (bpf_counter_skip(evsel)) + return 0; + return evsel->bpf_counter_ops->disable(evsel); +} + +int bpf_counter__read(struct evsel *evsel) +{ + if (bpf_counter_skip(evsel)) + return -EAGAIN; + return evsel->bpf_counter_ops->read(evsel); +} + +void bpf_counter__destroy(struct evsel *evsel) +{ + if (bpf_counter_skip(evsel)) + return; + evsel->bpf_counter_ops->destroy(evsel); + evsel->bpf_counter_ops = NULL; +} |