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-rw-r--r--tools/perf/util/bpf_lock_contention.c124
1 files changed, 122 insertions, 2 deletions
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index 31ff19afc2..b4cb3fe5cc 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -179,6 +179,123 @@ int lock_contention_prepare(struct lock_contention *con)
return 0;
}
+/*
+ * Run the BPF program directly using BPF_PROG_TEST_RUN to update the end
+ * timestamp in ktime so that it can calculate delta easily.
+ */
+static void mark_end_timestamp(void)
+{
+ DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
+ .flags = BPF_F_TEST_RUN_ON_CPU,
+ );
+ int prog_fd = bpf_program__fd(skel->progs.end_timestamp);
+
+ bpf_prog_test_run_opts(prog_fd, &opts);
+}
+
+static void update_lock_stat(int map_fd, int pid, u64 end_ts,
+ enum lock_aggr_mode aggr_mode,
+ struct tstamp_data *ts_data)
+{
+ u64 delta;
+ struct contention_key stat_key = {};
+ struct contention_data stat_data;
+
+ if (ts_data->timestamp >= end_ts)
+ return;
+
+ delta = end_ts - ts_data->timestamp;
+
+ switch (aggr_mode) {
+ case LOCK_AGGR_CALLER:
+ stat_key.stack_id = ts_data->stack_id;
+ break;
+ case LOCK_AGGR_TASK:
+ stat_key.pid = pid;
+ break;
+ case LOCK_AGGR_ADDR:
+ stat_key.lock_addr_or_cgroup = ts_data->lock;
+ break;
+ case LOCK_AGGR_CGROUP:
+ /* TODO */
+ return;
+ default:
+ return;
+ }
+
+ if (bpf_map_lookup_elem(map_fd, &stat_key, &stat_data) < 0)
+ return;
+
+ stat_data.total_time += delta;
+ stat_data.count++;
+
+ if (delta > stat_data.max_time)
+ stat_data.max_time = delta;
+ if (delta < stat_data.min_time)
+ stat_data.min_time = delta;
+
+ bpf_map_update_elem(map_fd, &stat_key, &stat_data, BPF_EXIST);
+}
+
+/*
+ * Account entries in the tstamp map (which didn't see the corresponding
+ * lock:contention_end tracepoint) using end_ts.
+ */
+static void account_end_timestamp(struct lock_contention *con)
+{
+ int ts_fd, stat_fd;
+ int *prev_key, key;
+ u64 end_ts = skel->bss->end_ts;
+ int total_cpus;
+ enum lock_aggr_mode aggr_mode = con->aggr_mode;
+ struct tstamp_data ts_data, *cpu_data;
+
+ /* Iterate per-task tstamp map (key = TID) */
+ ts_fd = bpf_map__fd(skel->maps.tstamp);
+ stat_fd = bpf_map__fd(skel->maps.lock_stat);
+
+ prev_key = NULL;
+ while (!bpf_map_get_next_key(ts_fd, prev_key, &key)) {
+ if (bpf_map_lookup_elem(ts_fd, &key, &ts_data) == 0) {
+ int pid = key;
+
+ if (aggr_mode == LOCK_AGGR_TASK && con->owner)
+ pid = ts_data.flags;
+
+ update_lock_stat(stat_fd, pid, end_ts, aggr_mode,
+ &ts_data);
+ }
+
+ prev_key = &key;
+ }
+
+ /* Now it'll check per-cpu tstamp map which doesn't have TID. */
+ if (aggr_mode == LOCK_AGGR_TASK || aggr_mode == LOCK_AGGR_CGROUP)
+ return;
+
+ total_cpus = cpu__max_cpu().cpu;
+ ts_fd = bpf_map__fd(skel->maps.tstamp_cpu);
+
+ cpu_data = calloc(total_cpus, sizeof(*cpu_data));
+ if (cpu_data == NULL)
+ return;
+
+ prev_key = NULL;
+ while (!bpf_map_get_next_key(ts_fd, prev_key, &key)) {
+ if (bpf_map_lookup_elem(ts_fd, &key, cpu_data) < 0)
+ goto next;
+
+ for (int i = 0; i < total_cpus; i++) {
+ update_lock_stat(stat_fd, -1, end_ts, aggr_mode,
+ &cpu_data[i]);
+ }
+
+next:
+ prev_key = &key;
+ }
+ free(cpu_data);
+}
+
int lock_contention_start(void)
{
skel->bss->enabled = 1;
@@ -188,6 +305,7 @@ int lock_contention_start(void)
int lock_contention_stop(void)
{
skel->bss->enabled = 0;
+ mark_end_timestamp();
return 0;
}
@@ -210,7 +328,7 @@ static const char *lock_contention_get_name(struct lock_contention *con,
/* do not update idle comm which contains CPU number */
if (pid) {
- struct thread *t = __machine__findnew_thread(machine, /*pid=*/-1, pid);
+ struct thread *t = machine__findnew_thread(machine, /*pid=*/-1, pid);
if (t == NULL)
return name;
@@ -301,8 +419,10 @@ int lock_contention_read(struct lock_contention *con)
if (stack_trace == NULL)
return -1;
+ account_end_timestamp(con);
+
if (con->aggr_mode == LOCK_AGGR_TASK) {
- struct thread *idle = __machine__findnew_thread(machine,
+ struct thread *idle = machine__findnew_thread(machine,
/*pid=*/0,
/*tid=*/0);
thread__set_comm(idle, "swapper", /*timestamp=*/0);