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Date: Wed, 20 Jul 2022 21:36:42 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...nel.org>
Cc: Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
LKML <linux-kernel@...r.kernel.org>,
Ian Rogers <irogers@...gle.com>,
linux-perf-users@...r.kernel.org, Will Deacon <will@...nel.org>,
Waiman Long <longman@...hat.com>,
Boqun Feng <boqun.feng@...il.com>,
Davidlohr Bueso <dave@...olabs.net>
Subject: [PATCH 4/6] perf lock: Add 'contention' subcommand
The 'perf lock contention' processes the lock contention events and
displays the result like perf lock report. Right now, there's not
much difference between the two but the lock contention specific
features will come soon.
$ perf lock contention
contended total wait max wait avg wait type caller
238 1.41 ms 29.20 us 5.94 us spinlock update_blocked_averages+0x4c
1 902.08 us 902.08 us 902.08 us rwsem:R do_user_addr_fault+0x1dd
81 330.30 us 17.24 us 4.08 us spinlock _nohz_idle_balance+0x172
2 89.54 us 61.26 us 44.77 us spinlock do_anonymous_page+0x16d
24 78.36 us 12.27 us 3.27 us mutex pipe_read+0x56
2 71.58 us 59.56 us 35.79 us spinlock __handle_mm_fault+0x6aa
6 25.68 us 6.89 us 4.28 us spinlock do_idle+0x28d
1 18.46 us 18.46 us 18.46 us rtmutex exec_fw_cmd+0x21b
3 15.25 us 6.26 us 5.08 us spinlock tick_do_update_jiffies64+0x2c
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/Documentation/perf-lock.txt | 4 +-
tools/perf/builtin-lock.c | 214 ++++++++++++++++++++++++-
2 files changed, 215 insertions(+), 3 deletions(-)
diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
index 4b8568f0c53b..da0bcbc676a3 100644
--- a/tools/perf/Documentation/perf-lock.txt
+++ b/tools/perf/Documentation/perf-lock.txt
@@ -8,7 +8,7 @@ perf-lock - Analyze lock events
SYNOPSIS
--------
[verse]
-'perf lock' {record|report|script|info}
+'perf lock' {record|report|script|info|contention}
DESCRIPTION
-----------
@@ -27,6 +27,8 @@ and statistics with this 'perf lock' command.
'perf lock info' shows metadata like threads or addresses
of lock instances.
+ 'perf lock contention' shows contention statistics.
+
COMMON OPTIONS
--------------
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 551bad905139..64f635273660 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -145,6 +145,18 @@ static enum {
*/
#define CONTENTION_STACK_SKIP 3
+/*
+ * flags for lock:contention_begin
+ * Imported from include/trace/events/lock.h.
+ */
+#define LCB_F_SPIN (1U << 0)
+#define LCB_F_READ (1U << 1)
+#define LCB_F_WRITE (1U << 2)
+#define LCB_F_RT (1U << 3)
+#define LCB_F_PERCPU (1U << 4)
+#define LCB_F_MUTEX (1U << 5)
+
+
static u64 sched_text_start;
static u64 sched_text_end;
static u64 lock_text_start;
@@ -1022,6 +1034,51 @@ static int lock_contention_caller(struct evsel *evsel, struct perf_sample *sampl
return -1;
}
+static u64 callchain_id(struct evsel *evsel, struct perf_sample *sample)
+{
+ struct callchain_cursor *cursor = &callchain_cursor;
+ struct thread *thread;
+ u64 hash = 0;
+ int skip = 0;
+ int ret;
+
+ thread = machine__findnew_thread(&session->machines.host,
+ -1, sample->pid);
+ if (thread == NULL)
+ return -1;
+
+ /* use caller function name from the callchain */
+ ret = thread__resolve_callchain(thread, cursor, evsel, sample,
+ NULL, NULL, CONTENTION_STACK_DEPTH);
+ thread__put(thread);
+
+ if (ret != 0)
+ return -1;
+
+ callchain_cursor_commit(cursor);
+
+ while (true) {
+ struct callchain_cursor_node *node;
+
+ node = callchain_cursor_current(cursor);
+ if (node == NULL)
+ break;
+
+ /* skip first few entries - for lock functions */
+ if (++skip <= CONTENTION_STACK_SKIP)
+ goto next;
+
+ if (node->ms.sym && is_lock_function(node->ip))
+ goto next;
+
+ hash ^= hash_long((unsigned long)node->ip, 64);
+
+next:
+ callchain_cursor_advance(cursor);
+ }
+ return hash;
+}
+
static int report_lock_contention_begin_event(struct evsel *evsel,
struct perf_sample *sample)
{
@@ -1039,6 +1096,8 @@ static int report_lock_contention_begin_event(struct evsel *evsel,
key = sample->tid;
break;
case LOCK_AGGR_CALLER:
+ key = callchain_id(evsel, sample);
+ break;
default:
pr_err("Invalid aggregation mode: %d\n", aggr_mode);
return -EINVAL;
@@ -1120,12 +1179,14 @@ static int report_lock_contention_end_event(struct evsel *evsel,
key = sample->tid;
break;
case LOCK_AGGR_CALLER:
+ key = callchain_id(evsel, sample);
+ break;
default:
pr_err("Invalid aggregation mode: %d\n", aggr_mode);
return -EINVAL;
}
- ls = lock_stat_find(addr);
+ ls = lock_stat_find(key);
if (!ls)
return 0;
@@ -1183,6 +1244,12 @@ static struct trace_lock_handler report_lock_ops = {
.contention_end_event = report_lock_contention_end_event,
};
+static struct trace_lock_handler contention_lock_ops = {
+ .contention_begin_event = report_lock_contention_begin_event,
+ .contention_end_event = report_lock_contention_end_event,
+};
+
+
static struct trace_lock_handler *trace_handler;
static int evsel__process_lock_acquire(struct evsel *evsel, struct perf_sample *sample)
@@ -1428,6 +1495,67 @@ static void sort_result(void)
}
}
+static const char *get_type_str(struct lock_stat *st)
+{
+ static const struct {
+ unsigned int flags;
+ const char *name;
+ } table[] = {
+ { 0, "semaphore" },
+ { LCB_F_SPIN, "spinlock" },
+ { LCB_F_SPIN | LCB_F_READ, "rwlock:R" },
+ { LCB_F_SPIN | LCB_F_WRITE, "rwlock:W"},
+ { LCB_F_READ, "rwsem:R" },
+ { LCB_F_WRITE, "rwsem:W" },
+ { LCB_F_RT, "rtmutex" },
+ { LCB_F_RT | LCB_F_READ, "rwlock-rt:R" },
+ { LCB_F_RT | LCB_F_WRITE, "rwlock-rt:W"},
+ { LCB_F_PERCPU | LCB_F_READ, "pcpu-sem:R" },
+ { LCB_F_PERCPU | LCB_F_WRITE, "pcpu-sem:W" },
+ { LCB_F_MUTEX, "mutex" },
+ { LCB_F_MUTEX | LCB_F_SPIN, "mutex" },
+ };
+
+ for (unsigned int i = 0; i < ARRAY_SIZE(table); i++) {
+ if (table[i].flags == st->flags)
+ return table[i].name;
+ }
+ return "unknown";
+}
+
+static void sort_contention_result(void)
+{
+ sort_result();
+}
+
+static void print_contention_result(void)
+{
+ struct lock_stat *st;
+ struct lock_key *key;
+ int bad, total;
+
+ list_for_each_entry(key, &lock_keys, list)
+ pr_info("%*s ", key->len, key->header);
+
+ pr_info(" %10s %s\n\n", "type", "caller");
+
+ bad = total = 0;
+ while ((st = pop_from_result())) {
+ total++;
+ if (st->broken)
+ bad++;
+
+ list_for_each_entry(key, &lock_keys, list) {
+ key->print(key, st);
+ pr_info(" ");
+ }
+
+ pr_info(" %10s %s\n", get_type_str(st), st->name);
+ }
+
+ print_bad_events(bad, total);
+}
+
static const struct evsel_str_handler lock_tracepoints[] = {
{ "lock:lock_acquire", evsel__process_lock_acquire, }, /* CONFIG_LOCKDEP */
{ "lock:lock_acquired", evsel__process_lock_acquired, }, /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */
@@ -1508,6 +1636,68 @@ static int __cmd_report(bool display_info)
return err;
}
+static int __cmd_contention(void)
+{
+ int err = -EINVAL;
+ struct perf_tool eops = {
+ .sample = process_sample_event,
+ .comm = perf_event__process_comm,
+ .mmap = perf_event__process_mmap,
+ .ordered_events = true,
+ };
+ struct perf_data data = {
+ .path = input_name,
+ .mode = PERF_DATA_MODE_READ,
+ .force = force,
+ };
+
+ session = perf_session__new(&data, &eops);
+ if (IS_ERR(session)) {
+ pr_err("Initializing perf session failed\n");
+ return PTR_ERR(session);
+ }
+
+ /* for lock function check */
+ symbol_conf.sort_by_name = true;
+ symbol__init(&session->header.env);
+
+ if (!perf_session__has_traces(session, "lock record"))
+ goto out_delete;
+
+ if (!evlist__find_evsel_by_str(session->evlist, "lock:contention_begin")) {
+ pr_err("lock contention evsel not found\n");
+ goto out_delete;
+ }
+
+ if (perf_session__set_tracepoints_handlers(session, contention_tracepoints)) {
+ pr_err("Initializing perf session tracepoint handlers failed\n");
+ goto out_delete;
+ }
+
+ if (setup_output_field("contended,wait_total,wait_max,avg_wait"))
+ goto out_delete;
+
+ sort_key = "wait_total";
+ if (select_key())
+ goto out_delete;
+
+ aggr_mode = LOCK_AGGR_CALLER;
+
+ err = perf_session__process_events(session);
+ if (err)
+ goto out_delete;
+
+ setup_pager();
+
+ sort_contention_result();
+ print_contention_result();
+
+out_delete:
+ perf_session__delete(session);
+ return err;
+}
+
+
static int __cmd_record(int argc, const char **argv)
{
const char *record_args[] = {
@@ -1626,12 +1816,17 @@ int cmd_lock(int argc, const char **argv)
OPT_PARENT(lock_options)
};
+ const struct option contention_options[] = {
+ OPT_PARENT(lock_options)
+ };
+
const char * const info_usage[] = {
"perf lock info [<options>]",
NULL
};
const char *const lock_subcommands[] = { "record", "report", "script",
- "info", NULL };
+ "info", "contention",
+ "contention", NULL };
const char *lock_usage[] = {
NULL,
NULL
@@ -1640,6 +1835,10 @@ int cmd_lock(int argc, const char **argv)
"perf lock report [<options>]",
NULL
};
+ const char * const contention_usage[] = {
+ "perf lock contention [<options>]",
+ NULL
+ };
unsigned int i;
int rc = 0;
@@ -1675,6 +1874,17 @@ int cmd_lock(int argc, const char **argv)
/* recycling report_lock_ops */
trace_handler = &report_lock_ops;
rc = __cmd_report(true);
+ } else if (strlen(argv[0]) > 2 && strstarts("contention", argv[0])) {
+ trace_handler = &contention_lock_ops;
+ if (argc) {
+ argc = parse_options(argc, argv, contention_options,
+ contention_usage, 0);
+ if (argc) {
+ usage_with_options(contention_usage,
+ contention_options);
+ }
+ }
+ rc = __cmd_contention();
} else {
usage_with_options(lock_usage, lock_options);
}
--
2.37.0.170.g444d1eabd0-goog
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