perf lock contention: Show per-cpu rq_lock with address

Using the BPF_PROG_RUN mechanism, we can run a raw_tp BPF program to
collect some semi-global locks like per-cpu locks.  Let's add runqueue
locks using bpf_per_cpu_ptr() helper.

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

         248      3.25 ms     32.23 us     13.10 us   ffff8cc75cfd2940   siglock
          60    217.91 us      9.69 us      3.63 us   ffff8cc700061c00
           8     70.23 us     13.86 us      8.78 us   ffff8cc703629484
           4     56.32 us     35.81 us     14.08 us   ffff8cc78b66f778   mmap_lock
           4     16.70 us      5.18 us      4.18 us   ffff8cc7036a0684
           3      4.99 us      2.65 us      1.66 us   ffff8d053da30c80   rq_lock
           2      3.44 us      2.28 us      1.72 us   ffff8d053dcf0c80   rq_lock
           9      2.51 us       371 ns       278 ns   ffff8ccb92479440
           2      2.11 us      1.24 us      1.06 us   ffff8d053db30c80   rq_lock
           2      2.06 us      1.69 us      1.03 us   ffff8d053d970c80   rq_lock

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230313204825.2665483-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 25 insertions, 2 deletions

diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index 51631af3b4d6..235fc7150545 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -151,6 +151,8 @@ int lock_contention_prepare(struct lock_contention *con)
 	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;
 }
@@ -198,14 +200,26 @@ static const char *lock_contention_get_name(struct lock_contention *con,
 	}
 
 	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)
-			name = sym->name;
-		return name;
+			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 */
@@ -258,6 +272,15 @@ int lock_contention_read(struct lock_contention *con)
 		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));