perf lock contention: Add -l/--lock-addr option

The -l/--lock-addr option is to implement per-lock-instance contention
stat using LOCK_AGGR_ADDR.  It displays lock address and optionally
symbol name if exists.

  $ sudo ./perf lock con -abl sleep 1
   contended   total wait     max wait     avg wait            address   symbol

           1     36.28 us     36.28 us     36.28 us   ffff92615d6448b8
           9     10.91 us      1.84 us      1.21 us   ffffffffbaed50c0   rcu_state
           1     10.49 us     10.49 us     10.49 us   ffff9262ac4f0c80
           8      4.68 us      1.67 us       585 ns   ffffffffbae07a40   jiffies_lock
           3      3.03 us      1.45 us      1.01 us   ffff9262277861e0
           1       924 ns       924 ns       924 ns   ffff926095ba9d20
           1       436 ns       436 ns       436 ns   ffff9260bfda4f60

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221209190727.759804-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
index 4958a1f..38e79d4 100644 (file)
--- a/tools/perf/Documentation/perf-lock.txt
+++ b/tools/perf/Documentation/perf-lock.txt
@@ -168,6 +168,10 @@ CONTENTION OPTIONS
 --entries=<value>::
        Display this many entries.
 
+-l::
+--lock-addr::
+       Show lock contention stat by address
+
 
 SEE ALSO
 --------

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 6fa3cdf..25c0a5e 100644 (file)
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -56,6 +56,7 @@ static struct rb_root         thread_stats;
 
 static bool combine_locks;
 static bool show_thread_stats;
+static bool show_lock_addrs;
 static bool use_bpf;
 static unsigned long bpf_map_entries = 10240;
 static int max_stack_depth = CONTENTION_STACK_DEPTH;
@@ -999,13 +1000,32 @@ static int report_lock_contention_begin_event(struct evsel *evsel,
        ls = lock_stat_find(key);
        if (!ls) {
                char buf[128];
-               const char *caller = buf;
+               const char *name = "";
                unsigned int flags = evsel__intval(evsel, sample, "flags");
+               struct machine *machine = &session->machines.host;
+               struct map *kmap;
+               struct symbol *sym;
+
+               switch (aggr_mode) {
+               case LOCK_AGGR_ADDR:
+                       /* make sure it loads the kernel map to find lock symbols */
+                       map__load(machine__kernel_map(machine));
+
+                       sym = machine__find_kernel_symbol(machine, key, &kmap);
+                       if (sym)
+                               name = sym->name;
+                       break;
+               case LOCK_AGGR_CALLER:
+                       name = buf;
+                       if (lock_contention_caller(evsel, sample, buf, sizeof(buf)) < 0)
+                               name = "Unknown";
+                       break;
+               case LOCK_AGGR_TASK:
+               default:
+                       break;
+               }
 
-               if (lock_contention_caller(evsel, sample, buf, sizeof(buf)) < 0)
-                       caller = "Unknown";
-
-               ls = lock_stat_findnew(key, caller, flags);
+               ls = lock_stat_findnew(key, name, flags);
                if (!ls)
                        return -ENOMEM;
 
@@ -1460,10 +1480,19 @@ static void print_contention_result(struct lock_contention *con)
                list_for_each_entry(key, &lock_keys, list)
                        pr_info("%*s ", key->len, key->header);
 
-               if (show_thread_stats)
+               switch (aggr_mode) {
+               case LOCK_AGGR_TASK:
                        pr_info("  %10s   %s\n\n", "pid", "comm");
-               else
+                       break;
+               case LOCK_AGGR_CALLER:
                        pr_info("  %10s   %s\n\n", "type", "caller");
+                       break;
+               case LOCK_AGGR_ADDR:
+                       pr_info("  %16s   %s\n\n", "address", "symbol");
+                       break;
+               default:
+                       break;
+               }
        }
 
        bad = total = printed = 0;
@@ -1471,6 +1500,9 @@ static void print_contention_result(struct lock_contention *con)
                bad = bad_hist[BROKEN_CONTENDED];
 
        while ((st = pop_from_result())) {
+               struct thread *t;
+               int pid;
+
                total += use_bpf ? st->nr_contended : 1;
                if (st->broken)
                        bad++;
@@ -1480,18 +1512,24 @@ static void print_contention_result(struct lock_contention *con)
                        pr_info(" ");
                }
 
-               if (show_thread_stats) {
-                       struct thread *t;
-                       int pid = st->addr;
-
-                       /* st->addr contains tid of thread */
+               switch (aggr_mode) {
+               case LOCK_AGGR_CALLER:
+                       pr_info("  %10s   %s\n", get_type_str(st), st->name);
+                       break;
+               case LOCK_AGGR_TASK:
+                       pid = st->addr;
                        t = perf_session__findnew(session, pid);
                        pr_info("  %10d   %s\n", pid, thread__comm_str(t));
-                       goto next;
+                       break;
+               case LOCK_AGGR_ADDR:
+                       pr_info("  %016llx   %s\n", (unsigned long long)st->addr,
+                               st->name ? : "");
+                       break;
+               default:
+                       break;
                }
 
-               pr_info("  %10s   %s\n", get_type_str(st), st->name);
-               if (verbose) {
+               if (aggr_mode == LOCK_AGGR_CALLER && verbose) {
                        struct map *kmap;
                        struct symbol *sym;
                        char buf[128];
@@ -1508,7 +1546,6 @@ static void print_contention_result(struct lock_contention *con)
                        }
                }
 
-next:
                if (++printed >= print_nr_entries)
                        break;
        }
@@ -1616,7 +1653,6 @@ static int __cmd_contention(int argc, const char **argv)
                .map_nr_entries = bpf_map_entries,
                .max_stack = max_stack_depth,
                .stack_skip = stack_skip,
-               .aggr_mode = show_thread_stats ? LOCK_AGGR_TASK : LOCK_AGGR_CALLER,
        };
 
        session = perf_session__new(use_bpf ? NULL : &data, &eops);
@@ -1627,6 +1663,9 @@ static int __cmd_contention(int argc, const char **argv)
 
        con.machine = &session->machines.host;
 
+       con.aggr_mode = aggr_mode = show_thread_stats ? LOCK_AGGR_TASK :
+               show_lock_addrs ? LOCK_AGGR_ADDR : LOCK_AGGR_CALLER;
+
        /* for lock function check */
        symbol_conf.sort_by_name = true;
        symbol__init(&session->header.env);
@@ -1907,6 +1946,7 @@ int cmd_lock(int argc, const char **argv)
                    "Set the number of stack depth to skip when finding a lock caller, "
                    "Default: " __stringify(CONTENTION_STACK_SKIP)),
        OPT_INTEGER('E', "entries", &print_nr_entries, "display this many functions"),
+       OPT_BOOLEAN('l', "lock-addr", &show_lock_addrs, "show lock stats by address"),
        OPT_PARENT(lock_options)
        };
 
@@ -1976,6 +2016,16 @@ int cmd_lock(int argc, const char **argv)
                        argc = parse_options(argc, argv, contention_options,
                                             contention_usage, 0);
                }
+
+               if (show_thread_stats && show_lock_addrs) {
+                       pr_err("Cannot use thread and addr mode together\n");
+                       parse_options_usage(contention_usage, contention_options,
+                                           "threads", 0);
+                       parse_options_usage(NULL, contention_options,
+                                           "lock-addr", 0);
+                       return -1;
+               }
+
                rc = __cmd_contention(argc, argv);
        } else {
                usage_with_options(lock_usage, lock_options);

diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index 1590a9f..8e1b791 100644 (file)
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -137,11 +137,15 @@ int lock_contention_read(struct lock_contention *con)
                thread__set_comm(idle, "swapper", /*timestamp=*/0);
        }
 
+       /* make sure it loads the kernel map */
+       map__load(maps__first(machine->kmaps));
+
        prev_key = NULL;
        while (!bpf_map_get_next_key(fd, prev_key, &key)) {
                struct map *kmap;
                struct symbol *sym;
                int idx = 0;
+               s32 stack_id;
 
                /* to handle errors in the loop body */
                err = -1;
@@ -160,24 +164,31 @@ int lock_contention_read(struct lock_contention *con)
                        st->avg_wait_time = data.total_time / data.count;
 
                st->flags = data.flags;
+               st->addr = key.aggr_key;
 
                if (con->aggr_mode == LOCK_AGGR_TASK) {
                        struct contention_task_data task;
                        struct thread *t;
-
-                       st->addr = key.stack_or_task_id;
+                       int pid = key.aggr_key;
 
                        /* do not update idle comm which contains CPU number */
                        if (st->addr) {
-                               bpf_map_lookup_elem(task_fd, &key, &task);
-                               t = __machine__findnew_thread(machine, /*pid=*/-1,
-                                                             key.stack_or_task_id);
+                               bpf_map_lookup_elem(task_fd, &pid, &task);
+                               t = __machine__findnew_thread(machine, /*pid=*/-1, pid);
                                thread__set_comm(t, task.comm, /*timestamp=*/0);
                        }
                        goto next;
                }
 
-               bpf_map_lookup_elem(stack, &key, stack_trace);
+               if (con->aggr_mode == LOCK_AGGR_ADDR) {
+                       sym = machine__find_kernel_symbol(machine, st->addr, &kmap);
+                       if (sym)
+                               st->name = strdup(sym->name);
+                       goto next;
+               }
+
+               stack_id = key.aggr_key;
+               bpf_map_lookup_elem(stack, &stack_id, stack_trace);
 
                /* skip lock internal functions */
                while (machine__is_lock_function(machine, stack_trace[idx]) &&

diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index cd405ad..11b0fc7 100644 (file)
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -168,11 +168,20 @@ int contention_end(u64 *ctx)
 
        duration = bpf_ktime_get_ns() - pelem->timestamp;
 
-       if (aggr_mode == LOCK_AGGR_CALLER) {
-               key.stack_or_task_id = pelem->stack_id;
-       } else {
-               key.stack_or_task_id = pid;
+       switch (aggr_mode) {
+       case LOCK_AGGR_CALLER:
+               key.aggr_key = pelem->stack_id;
+               break;
+       case LOCK_AGGR_TASK:
+               key.aggr_key = pid;
                update_task_data(pid);
+               break;
+       case LOCK_AGGR_ADDR:
+               key.aggr_key = pelem->lock;
+               break;
+       default:
+               /* should not happen */
+               return 0;
        }
 
        data = bpf_map_lookup_elem(&lock_stat, &key);

diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h
index dbdf4ca..ce71cf1 100644 (file)
--- a/tools/perf/util/bpf_skel/lock_data.h
+++ b/tools/perf/util/bpf_skel/lock_data.h
@@ -4,7 +4,7 @@
 #define UTIL_BPF_SKEL_LOCK_DATA_H
 
 struct contention_key {
-       s32 stack_or_task_id;
+       u64 aggr_key;  /* can be stack_id, pid or lock addr */
 };
 
 #define TASK_COMM_LEN  16