perf lock contention: Add --lock-cgroup option

The --lock-cgroup option shows lock contention stats break down by
cgroups.

Add LOCK_AGGR_CGROUP mode and use it instead of use_cgroup field.

  $ sudo ./perf lock con -ab --lock-cgroup sleep 1
   contended   total wait     max wait     avg wait   cgroup

           8     15.70 us      6.34 us      1.96 us   /
           2      1.48 us       747 ns       738 ns   /user.slice/.../app.slice/app-gnome-google\x2dchrome-6442.scope
           1       848 ns       848 ns       848 ns   /user.slice/.../session.slice/org.gnome.Shell@x11.service
           1       220 ns       220 ns       220 ns   /user.slice/.../session.slice/pipewire-pulse.service

For now, the cgroup mode only works with BPF (-b).

Committer notes:

Remove -g as it is used in the other tools with a clear meaning of
collect/show callchains. As agreed with Namhyung off list.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@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/20230906174903.346486-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index c6bd7c9b2d57..42753a0dfdc5 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -152,7 +152,10 @@ int lock_contention_prepare(struct lock_contention *con)
 	skel->bss->needs_callstack = con->save_callstack;
 	skel->bss->lock_owner = con->owner;
 
-	if (con->use_cgroup) {
+	if (con->aggr_mode == LOCK_AGGR_CGROUP) {
+		if (cgroup_is_v2("perf_event"))
+			skel->bss->use_cgroup_v2 = 1;
+
 		read_all_cgroups(&con->cgroups);
 	}
 
@@ -214,12 +217,12 @@ static const char *lock_contention_get_name(struct lock_contention *con,
 			return "siglock";
 
 		/* global locks with symbols */
-		sym = machine__find_kernel_symbol(machine, key->lock_addr, &kmap);
+		sym = machine__find_kernel_symbol(machine, key->lock_addr_or_cgroup, &kmap);
 		if (sym)
 			return sym->name;
 
 		/* try semi-global locks collected separately */
-		if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr, &flags)) {
+		if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr_or_cgroup, &flags)) {
 			if (flags == LOCK_CLASS_RQLOCK)
 				return "rq_lock";
 		}
@@ -227,8 +230,8 @@ static const char *lock_contention_get_name(struct lock_contention *con,
 		return "";
 	}
 
-	if (con->use_cgroup) {
-		u64 cgrp_id = key->lock_addr;
+	if (con->aggr_mode == LOCK_AGGR_CGROUP) {
+		u64 cgrp_id = key->lock_addr_or_cgroup;
 		struct cgroup *cgrp = __cgroup__find(&con->cgroups, cgrp_id);
 
 		if (cgrp)
@@ -329,7 +332,8 @@ int lock_contention_read(struct lock_contention *con)
 			ls_key = key.pid;
 			break;
 		case LOCK_AGGR_ADDR:
-			ls_key = key.lock_addr;
+		case LOCK_AGGR_CGROUP:
+			ls_key = key.lock_addr_or_cgroup;
 			break;
 		default:
 			goto next;