perf lock: Allow concurrent record and report

To support live monitoring of kernel lock contention without BPF,
it should support something like below:

  # perf lock record -a -o- sleep 1 | perf lock contention -i-
   contended   total wait     max wait     avg wait         type   caller

           2     10.27 us      6.17 us      5.13 us     spinlock   load_balance+0xc03
           1      5.29 us      5.29 us      5.29 us     rwlock:W   ep_scan_ready_list+0x54
           1      4.12 us      4.12 us      4.12 us     spinlock   smpboot_thread_fn+0x116
           1      3.28 us      3.28 us      3.28 us        mutex   pipe_read+0x50

To do that, it needs to handle HEAD_ATTR, HEADER_EVENT_UPDATE and
HEADER_TRACING_DATA which are generated only for the pipe mode.
And setting event handler also should be delayed until it gets the
event information.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221104051440.220989-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 6f79175..0d28009 100644 (file)
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1390,6 +1390,34 @@ static int dump_info(void)
        return rc;
 }
 
+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 */
+       { "lock:lock_contended", evsel__process_lock_contended, }, /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */
+       { "lock:lock_release",   evsel__process_lock_release,   }, /* CONFIG_LOCKDEP */
+};
+
+static const struct evsel_str_handler contention_tracepoints[] = {
+       { "lock:contention_begin", evsel__process_contention_begin, },
+       { "lock:contention_end",   evsel__process_contention_end,   },
+};
+
+static int process_event_update(struct perf_tool *tool,
+                               union perf_event *event,
+                               struct evlist **pevlist)
+{
+       int ret;
+
+       ret = perf_event__process_event_update(tool, event, pevlist);
+       if (ret < 0)
+               return ret;
+
+       /* this can return -EEXIST since we call it for each evsel */
+       perf_session__set_tracepoints_handlers(session, lock_tracepoints);
+       perf_session__set_tracepoints_handlers(session, contention_tracepoints);
+       return 0;
+}
+
 typedef int (*tracepoint_handler)(struct evsel *evsel,
                                  struct perf_sample *sample);
 
@@ -1545,28 +1573,19 @@ next:
        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 */
-       { "lock:lock_contended", evsel__process_lock_contended, }, /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */
-       { "lock:lock_release",   evsel__process_lock_release,   }, /* CONFIG_LOCKDEP */
-};
-
-static const struct evsel_str_handler contention_tracepoints[] = {
-       { "lock:contention_begin", evsel__process_contention_begin, },
-       { "lock:contention_end",   evsel__process_contention_end,   },
-};
-
 static bool force;
 
 static int __cmd_report(bool display_info)
 {
        int err = -EINVAL;
        struct perf_tool eops = {
+               .attr            = perf_event__process_attr,
+               .event_update    = process_event_update,
                .sample          = process_sample_event,
                .comm            = perf_event__process_comm,
                .mmap            = perf_event__process_mmap,
                .namespaces      = perf_event__process_namespaces,
+               .tracing_data    = perf_event__process_tracing_data,
                .ordered_events  = true,
        };
        struct perf_data data = {
@@ -1585,17 +1604,19 @@ static int __cmd_report(bool display_info)
        symbol_conf.sort_by_name = true;
        symbol__init(&session->header.env);
 
-       if (!perf_session__has_traces(session, "lock record"))
-               goto out_delete;
+       if (!data.is_pipe) {
+               if (!perf_session__has_traces(session, "lock record"))
+                       goto out_delete;
 
-       if (perf_session__set_tracepoints_handlers(session, lock_tracepoints)) {
-               pr_err("Initializing perf session tracepoint handlers failed\n");
-               goto out_delete;
-       }
+               if (perf_session__set_tracepoints_handlers(session, lock_tracepoints)) {
+                       pr_err("Initializing perf session tracepoint handlers failed\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 (perf_session__set_tracepoints_handlers(session, contention_tracepoints)) {
+                       pr_err("Initializing perf session tracepoint handlers failed\n");
+                       goto out_delete;
+               }
        }
 
        if (setup_output_field(false, output_fields))
@@ -1633,9 +1654,12 @@ static int __cmd_contention(int argc, const char **argv)
 {
        int err = -EINVAL;
        struct perf_tool eops = {
+               .attr            = perf_event__process_attr,
+               .event_update    = process_event_update,
                .sample          = process_sample_event,
                .comm            = perf_event__process_comm,
                .mmap            = perf_event__process_mmap,
+               .tracing_data    = perf_event__process_tracing_data,
                .ordered_events  = true,
        };
        struct perf_data data = {
@@ -1698,7 +1722,7 @@ static int __cmd_contention(int argc, const char **argv)
                        pr_err("lock contention BPF setup failed\n");
                        goto out_delete;
                }
-       } else {
+       } else if (!data.is_pipe) {
                if (!perf_session__has_traces(session, "lock record"))
                        goto out_delete;
 

diff --git a/tools/perf/tests/shell/lock_contention.sh b/tools/perf/tests/shell/lock_contention.sh
index 04bf604..f7bd0d8 100755 (executable)
--- a/tools/perf/tests/shell/lock_contention.sh
+++ b/tools/perf/tests/shell/lock_contention.sh
@@ -53,7 +53,7 @@ test_bpf()
 
        if ! perf lock con -b true > /dev/null 2>&1 ; then
                echo "[Skip] No BPF support"
-               exit
+               return
        fi
 
        # the perf lock contention output goes to the stderr
@@ -65,9 +65,22 @@ test_bpf()
        fi
 }
 
+test_record_concurrent()
+{
+       echo "Testing perf lock record and perf lock contention at the same time"
+       perf lock record -o- -- perf bench sched messaging 2> /dev/null | \
+       perf lock contention -i- -E 1 -q 2> ${result}
+       if [ $(cat "${result}" | wc -l) != "1" ]; then
+               echo "[Fail] Recorded result count is not 1:" $(cat "${result}" | wc -l)
+               err=1
+               exit
+       fi
+}
+
 check
 
 test_record
 test_bpf
+test_record_concurrent
 
 exit ${err}