[PATCH 2/4] perf lock contention: Track and show siglock with address

Namhyung Kim
2023-03-13T20:49:06Z

Likewise, we can display siglock by following the pointer like
current->sighand->siglock.

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

16 2.18 ms 305.35 us 136.34 us ffffffff92e06080 tasklist_lock
28 521.78 us 31.16 us 18.63 us ffff8cc703783ec4
7 119.03 us 23.55 us 17.00 us ffff8ccb92479440
15 88.29 us 10.06 us 5.89 us ffff8cd560b5f380 siglock
7 37.67 us 9.16 us 5.38 us ffff8d053daf0c80
5 8.81 us 4.92 us 1.76 us ffff8d053d6b0c80

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/builtin-lock.c | 3 +--
tools/perf/util/bpf_lock_contention.c | 8 ++++++--
tools/perf/util/bpf_skel/lock_contention.bpf.c | 5 +++++
tools/perf/util/bpf_skel/lock_data.h | 3 ++-
4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index c62f4d9363a6..c710a5d46638 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1662,8 +1662,7 @@ static void print_contention_result(struct lock_contention *con)
pid, pid == -1 ? "Unknown" : thread__comm_str(t));
break;
case LOCK_AGGR_ADDR:
- pr_info(" %016llx %s\n", (unsigned long long)st->addr,
- (st->flags & LCD_F_MMAP_LOCK) ? "mmap_lock" : st->name);
+ pr_info(" %016llx %s\n", (unsigned long long)st->addr, st->name);
break;
default:
break;
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index fadcacb9d501..51631af3b4d6 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -169,7 +169,7 @@ int lock_contention_stop(void)

static const char *lock_contention_get_name(struct lock_contention *con,
struct contention_key *key,
- u64 *stack_trace)
+ u64 *stack_trace, u32 flags)
{
int idx = 0;
u64 addr;
@@ -198,6 +198,10 @@ static const char *lock_contention_get_name(struct lock_contention *con,
}

if (con->aggr_mode == LOCK_AGGR_ADDR) {
+ if (flags & LCD_F_MMAP_LOCK)
+ return "mmap_lock";
+ if (flags & LCD_F_SIGHAND_LOCK)
+ return "siglock";
sym = machine__find_kernel_symbol(machine, key->lock_addr, &kmap);
if (sym)
name = sym->name;
@@ -301,7 +305,7 @@ int lock_contention_read(struct lock_contention *con)
goto next;
}

- name = lock_contention_get_name(con, &key, stack_trace);
+ name = lock_contention_get_name(con, &key, stack_trace, data.flags);
st = lock_stat_findnew(ls_key, name, data.flags);
if (st == NULL)
break;
diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index f092a78ae2b5..4ba34caf84eb 100644
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -236,6 +236,11 @@ static inline __u32 check_lock_type(__u64 lock, __u32 flags)
return LCD_F_MMAP_LOCK;
}
break;
+ case LCB_F_SPIN: /* spinlock */
+ curr = bpf_get_current_task_btf();
+ if (&curr->sighand->siglock == (void *)lock)
+ return LCD_F_SIGHAND_LOCK;
+ break;
default:
break;
}
diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h
index 789f20833798..5ed1a0955015 100644
--- a/tools/perf/util/bpf_skel/lock_data.h
+++ b/tools/perf/util/bpf_skel/lock_data.h
@@ -19,7 +19,8 @@ struct contention_task_data {
* Upper bits of the flags in the contention_data are used to identify
* some well-known locks which do not have symbols (non-global locks).
*/
-#define LCD_F_MMAP_LOCK (1U << 31)
+#define LCD_F_MMAP_LOCK (1U << 31)
+#define LCD_F_SIGHAND_LOCK (1U << 30)

struct contention_data {
u64 total_time;
--
2.40.0.rc1.284.g88254d51c5-goog