diff options
Diffstat (limited to 'tools/perf/util/bpf_lock_contention.c')
-rw-r--r-- | tools/perf/util/bpf_lock_contention.c | 375 |
1 files changed, 375 insertions, 0 deletions
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c new file mode 100644 index 0000000000..e7dddf0127 --- /dev/null +++ b/tools/perf/util/bpf_lock_contention.c @@ -0,0 +1,375 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "util/debug.h" +#include "util/evlist.h" +#include "util/machine.h" +#include "util/map.h" +#include "util/symbol.h" +#include "util/target.h" +#include "util/thread.h" +#include "util/thread_map.h" +#include "util/lock-contention.h" +#include <linux/zalloc.h> +#include <linux/string.h> +#include <bpf/bpf.h> + +#include "bpf_skel/lock_contention.skel.h" +#include "bpf_skel/lock_data.h" + +static struct lock_contention_bpf *skel; + +int lock_contention_prepare(struct lock_contention *con) +{ + int i, fd; + int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1; + struct evlist *evlist = con->evlist; + struct target *target = con->target; + + skel = lock_contention_bpf__open(); + if (!skel) { + pr_err("Failed to open lock-contention BPF skeleton\n"); + return -1; + } + + bpf_map__set_value_size(skel->maps.stacks, con->max_stack * sizeof(u64)); + bpf_map__set_max_entries(skel->maps.lock_stat, con->map_nr_entries); + bpf_map__set_max_entries(skel->maps.tstamp, con->map_nr_entries); + + if (con->aggr_mode == LOCK_AGGR_TASK) + bpf_map__set_max_entries(skel->maps.task_data, con->map_nr_entries); + else + bpf_map__set_max_entries(skel->maps.task_data, 1); + + if (con->save_callstack) + bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries); + else + bpf_map__set_max_entries(skel->maps.stacks, 1); + + if (target__has_cpu(target)) + ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus); + if (target__has_task(target)) + ntasks = perf_thread_map__nr(evlist->core.threads); + if (con->filters->nr_types) + ntypes = con->filters->nr_types; + + /* resolve lock name filters to addr */ + if (con->filters->nr_syms) { + struct symbol *sym; + struct map *kmap; + unsigned long *addrs; + + for (i = 0; i < con->filters->nr_syms; i++) { + sym = machine__find_kernel_symbol_by_name(con->machine, + con->filters->syms[i], + &kmap); + if (sym == NULL) { + pr_warning("ignore unknown symbol: %s\n", + con->filters->syms[i]); + continue; + } + + addrs = realloc(con->filters->addrs, + (con->filters->nr_addrs + 1) * sizeof(*addrs)); + if (addrs == NULL) { + pr_warning("memory allocation failure\n"); + continue; + } + + addrs[con->filters->nr_addrs++] = map__unmap_ip(kmap, sym->start); + con->filters->addrs = addrs; + } + naddrs = con->filters->nr_addrs; + } + + bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus); + bpf_map__set_max_entries(skel->maps.task_filter, ntasks); + bpf_map__set_max_entries(skel->maps.type_filter, ntypes); + bpf_map__set_max_entries(skel->maps.addr_filter, naddrs); + + if (lock_contention_bpf__load(skel) < 0) { + pr_err("Failed to load lock-contention BPF skeleton\n"); + return -1; + } + + if (target__has_cpu(target)) { + u32 cpu; + u8 val = 1; + + skel->bss->has_cpu = 1; + fd = bpf_map__fd(skel->maps.cpu_filter); + + for (i = 0; i < ncpus; i++) { + cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu; + bpf_map_update_elem(fd, &cpu, &val, BPF_ANY); + } + } + + if (target__has_task(target)) { + u32 pid; + u8 val = 1; + + skel->bss->has_task = 1; + fd = bpf_map__fd(skel->maps.task_filter); + + for (i = 0; i < ntasks; i++) { + pid = perf_thread_map__pid(evlist->core.threads, i); + bpf_map_update_elem(fd, &pid, &val, BPF_ANY); + } + } + + if (target__none(target) && evlist->workload.pid > 0) { + u32 pid = evlist->workload.pid; + u8 val = 1; + + skel->bss->has_task = 1; + fd = bpf_map__fd(skel->maps.task_filter); + bpf_map_update_elem(fd, &pid, &val, BPF_ANY); + } + + if (con->filters->nr_types) { + u8 val = 1; + + skel->bss->has_type = 1; + fd = bpf_map__fd(skel->maps.type_filter); + + for (i = 0; i < con->filters->nr_types; i++) + bpf_map_update_elem(fd, &con->filters->types[i], &val, BPF_ANY); + } + + if (con->filters->nr_addrs) { + u8 val = 1; + + skel->bss->has_addr = 1; + fd = bpf_map__fd(skel->maps.addr_filter); + + for (i = 0; i < con->filters->nr_addrs; i++) + bpf_map_update_elem(fd, &con->filters->addrs[i], &val, BPF_ANY); + } + + /* these don't work well if in the rodata section */ + skel->bss->stack_skip = con->stack_skip; + skel->bss->aggr_mode = con->aggr_mode; + skel->bss->needs_callstack = con->save_callstack; + skel->bss->lock_owner = con->owner; + + bpf_program__set_autoload(skel->progs.collect_lock_syms, false); + + lock_contention_bpf__attach(skel); + return 0; +} + +int lock_contention_start(void) +{ + skel->bss->enabled = 1; + return 0; +} + +int lock_contention_stop(void) +{ + skel->bss->enabled = 0; + return 0; +} + +static const char *lock_contention_get_name(struct lock_contention *con, + struct contention_key *key, + u64 *stack_trace, u32 flags) +{ + int idx = 0; + u64 addr; + const char *name = ""; + static char name_buf[KSYM_NAME_LEN]; + struct symbol *sym; + struct map *kmap; + struct machine *machine = con->machine; + + if (con->aggr_mode == LOCK_AGGR_TASK) { + struct contention_task_data task; + int pid = key->pid; + int task_fd = bpf_map__fd(skel->maps.task_data); + + /* do not update idle comm which contains CPU number */ + if (pid) { + struct thread *t = __machine__findnew_thread(machine, /*pid=*/-1, pid); + + if (t == NULL) + return name; + if (!bpf_map_lookup_elem(task_fd, &pid, &task) && + thread__set_comm(t, task.comm, /*timestamp=*/0)) + name = task.comm; + } + return name; + } + + if (con->aggr_mode == LOCK_AGGR_ADDR) { + int lock_fd = bpf_map__fd(skel->maps.lock_syms); + + /* per-process locks set upper bits of the flags */ + if (flags & LCD_F_MMAP_LOCK) + return "mmap_lock"; + if (flags & LCD_F_SIGHAND_LOCK) + return "siglock"; + + /* global locks with symbols */ + sym = machine__find_kernel_symbol(machine, key->lock_addr, &kmap); + if (sym) + return sym->name; + + /* try semi-global locks collected separately */ + if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr, &flags)) { + if (flags == LOCK_CLASS_RQLOCK) + return "rq_lock"; + } + + return ""; + } + + /* LOCK_AGGR_CALLER: skip lock internal functions */ + while (machine__is_lock_function(machine, stack_trace[idx]) && + idx < con->max_stack - 1) + idx++; + + addr = stack_trace[idx]; + sym = machine__find_kernel_symbol(machine, addr, &kmap); + + if (sym) { + unsigned long offset; + + offset = map__map_ip(kmap, addr) - sym->start; + + if (offset == 0) + return sym->name; + + snprintf(name_buf, sizeof(name_buf), "%s+%#lx", sym->name, offset); + } else { + snprintf(name_buf, sizeof(name_buf), "%#lx", (unsigned long)addr); + } + + return name_buf; +} + +int lock_contention_read(struct lock_contention *con) +{ + int fd, stack, err = 0; + struct contention_key *prev_key, key = {}; + struct contention_data data = {}; + struct lock_stat *st = NULL; + struct machine *machine = con->machine; + u64 *stack_trace; + size_t stack_size = con->max_stack * sizeof(*stack_trace); + + fd = bpf_map__fd(skel->maps.lock_stat); + stack = bpf_map__fd(skel->maps.stacks); + + con->fails.task = skel->bss->task_fail; + con->fails.stack = skel->bss->stack_fail; + con->fails.time = skel->bss->time_fail; + con->fails.data = skel->bss->data_fail; + + stack_trace = zalloc(stack_size); + if (stack_trace == NULL) + return -1; + + if (con->aggr_mode == LOCK_AGGR_TASK) { + struct thread *idle = __machine__findnew_thread(machine, + /*pid=*/0, + /*tid=*/0); + thread__set_comm(idle, "swapper", /*timestamp=*/0); + } + + if (con->aggr_mode == LOCK_AGGR_ADDR) { + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts, + .flags = BPF_F_TEST_RUN_ON_CPU, + ); + int prog_fd = bpf_program__fd(skel->progs.collect_lock_syms); + + bpf_prog_test_run_opts(prog_fd, &opts); + } + + /* make sure it loads the kernel map */ + map__load(maps__first(machine->kmaps)->map); + + prev_key = NULL; + while (!bpf_map_get_next_key(fd, prev_key, &key)) { + s64 ls_key; + const char *name; + + /* to handle errors in the loop body */ + err = -1; + + bpf_map_lookup_elem(fd, &key, &data); + if (con->save_callstack) { + bpf_map_lookup_elem(stack, &key.stack_id, stack_trace); + + if (!match_callstack_filter(machine, stack_trace)) { + con->nr_filtered += data.count; + goto next; + } + } + + switch (con->aggr_mode) { + case LOCK_AGGR_CALLER: + ls_key = key.stack_id; + break; + case LOCK_AGGR_TASK: + ls_key = key.pid; + break; + case LOCK_AGGR_ADDR: + ls_key = key.lock_addr; + break; + default: + goto next; + } + + st = lock_stat_find(ls_key); + if (st != NULL) { + st->wait_time_total += data.total_time; + if (st->wait_time_max < data.max_time) + st->wait_time_max = data.max_time; + if (st->wait_time_min > data.min_time) + st->wait_time_min = data.min_time; + + st->nr_contended += data.count; + if (st->nr_contended) + st->avg_wait_time = st->wait_time_total / st->nr_contended; + goto next; + } + + name = lock_contention_get_name(con, &key, stack_trace, data.flags); + st = lock_stat_findnew(ls_key, name, data.flags); + if (st == NULL) + break; + + st->nr_contended = data.count; + st->wait_time_total = data.total_time; + st->wait_time_max = data.max_time; + st->wait_time_min = data.min_time; + + if (data.count) + st->avg_wait_time = data.total_time / data.count; + + if (con->aggr_mode == LOCK_AGGR_CALLER && verbose > 0) { + st->callstack = memdup(stack_trace, stack_size); + if (st->callstack == NULL) + break; + } + +next: + prev_key = &key; + + /* we're fine now, reset the error */ + err = 0; + } + + free(stack_trace); + + return err; +} + +int lock_contention_finish(void) +{ + if (skel) { + skel->bss->enabled = 0; + lock_contention_bpf__destroy(skel); + } + + return 0; +} |