[RFC v4 13/17] perf kwork: Implement perf kwork timehist

From: Yang Jihong
Date: Wed Jul 27 2022 - 05:07:32 EST

Implements framework of perf kwork timehist,
to provide an analysis of kernel work events.

Test cases:

# perf kwork tim
Runtime start Runtime end Cpu Kwork name Runtime Delaytime
(TYPE)NAME:NUM (msec) (msec)
----------------- ----------------- ------ ------------------------------ ---------- ----------
91576.060290 91576.060344 [0000] (s)RCU:9 0.055 0.111
91576.061470 91576.061547 [0000] (s)SCHED:7 0.077 0.073
91576.062604 91576.062697 [0001] (s)RCU:9 0.094 0.409
91576.064443 91576.064517 [0002] (s)RCU:9 0.074 0.114
91576.065144 91576.065211 [0000] (s)SCHED:7 0.067 0.058
91576.066564 91576.066609 [0003] (s)RCU:9 0.045 0.110
91576.068495 91576.068559 [0000] (s)SCHED:7 0.064 0.059
91576.068900 91576.068996 [0004] (s)RCU:9 0.096 0.726
91576.069364 91576.069420 [0002] (s)RCU:9 0.056 0.082
91576.069649 91576.069701 [0004] (s)RCU:9 0.052 0.111
91576.070147 91576.070206 [0000] (s)SCHED:7 0.060 0.057
91576.073147 91576.073202 [0000] (s)SCHED:7 0.054 0.060
<SNIP>

# perf kwork tim --max-stack 2 -g
Runtime start Runtime end Cpu Kwork name Runtime Delaytime
(TYPE)NAME:NUM (msec) (msec)
----------------- ----------------- ------ ------------------------------ ---------- ----------
91576.060290 91576.060344 [0000] (s)RCU:9 0.055 0.111 irq_exit_rcu <- sysvec_apic_timer_interrupt
91576.061470 91576.061547 [0000] (s)SCHED:7 0.077 0.073 irq_exit_rcu <- sysvec_call_function_single
91576.062604 91576.062697 [0001] (s)RCU:9 0.094 0.409 irq_exit_rcu <- sysvec_apic_timer_interrupt
91576.064443 91576.064517 [0002] (s)RCU:9 0.074 0.114 irq_exit_rcu <- sysvec_apic_timer_interrupt
91576.065144 91576.065211 [0000] (s)SCHED:7 0.067 0.058 irq_exit_rcu <- sysvec_call_function_single
91576.066564 91576.066609 [0003] (s)RCU:9 0.045 0.110 irq_exit_rcu <- sysvec_apic_timer_interrupt
91576.068495 91576.068559 [0000] (s)SCHED:7 0.064 0.059 irq_exit_rcu <- sysvec_call_function_single
91576.068900 91576.068996 [0004] (s)RCU:9 0.096 0.726 irq_exit_rcu <- sysvec_apic_timer_interrupt
91576.069364 91576.069420 [0002] (s)RCU:9 0.056 0.082 irq_exit_rcu <- sysvec_apic_timer_interrupt
91576.069649 91576.069701 [0004] (s)RCU:9 0.052 0.111 irq_exit_rcu <- sysvec_apic_timer_interrupt
<SNIP>

Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>
---
tools/perf/Documentation/perf-kwork.txt | 65 ++++++
tools/perf/builtin-kwork.c | 299 +++++++++++++++++++++++-
tools/perf/util/kwork.h | 3 +
3 files changed, 366 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-kwork.txt b/tools/perf/Documentation/perf-kwork.txt
index 069981457de1..51c1625bacae 100644
--- a/tools/perf/Documentation/perf-kwork.txt
+++ b/tools/perf/Documentation/perf-kwork.txt
@@ -21,10 +21,36 @@ There are several variants of 'perf kwork':

'perf kwork latency' to report the per kwork latencies.

+ 'perf kwork timehist' provides an analysis of kernel work events.
+
Example usage:
perf kwork record -- sleep 1
perf kwork report
perf kwork latency
+ perf kwork timehist
+
+ By default it shows the individual work events such as irq, workqeueu,
+ including the run time and delay (time between raise and actually entry):
+
+ Runtime start Runtime end Cpu Kwork name Runtime Delaytime
+ (TYPE)NAME:NUM (msec) (msec)
+ ----------------- ----------------- ------ ------------------------- ---------- ----------
+ 1811186.976062 1811186.976327 [0000] (s)RCU:9 0.266 0.114
+ 1811186.978452 1811186.978547 [0000] (s)SCHED:7 0.095 0.171
+ 1811186.980327 1811186.980490 [0000] (s)SCHED:7 0.162 0.083
+ 1811186.981221 1811186.981271 [0000] (s)SCHED:7 0.050 0.077
+ 1811186.984267 1811186.984318 [0000] (s)SCHED:7 0.051 0.075
+ 1811186.987252 1811186.987315 [0000] (s)SCHED:7 0.063 0.081
+ 1811186.987785 1811186.987843 [0006] (s)RCU:9 0.058 0.645
+ 1811186.988319 1811186.988383 [0000] (s)SCHED:7 0.064 0.143
+ 1811186.989404 1811186.989607 [0002] (s)TIMER:1 0.203 0.111
+ 1811186.989660 1811186.989732 [0002] (s)SCHED:7 0.072 0.310
+ 1811186.991295 1811186.991407 [0002] eth0:10 0.112
+ 1811186.991639 1811186.991734 [0002] (s)NET_RX:3 0.095 0.277
+ 1811186.989860 1811186.991826 [0002] (w)vmstat_shepherd 1.966 0.345
+ ...
+
+ Times are in msec.usec.

OPTIONS
-------
@@ -100,6 +126,45 @@ OPTIONS for 'perf kwork latency'
stop time is not given (i.e, time string is 'x.y,') then analysis goes
to end of file.

+OPTIONS for 'perf kwork timehist'
+---------------------------------
+
+-C::
+--cpu::
+ Only show events for the given CPU(s) (comma separated list).
+
+-g::
+--call-graph::
+ Display call chains if present (default off).
+
+-i::
+--input::
+ Input file name. (default: perf.data unless stdin is a fifo)
+
+-k::
+--vmlinux=<file>::
+ Vmlinux pathname
+
+-n::
+--name::
+ Only show events for the given name.
+
+--kallsyms=<file>::
+ Kallsyms pathname
+
+--max-stack::
+ Maximum number of functions to display in backtrace, default 5.
+
+--symfs=<directory>::
+ Look for files with symbols relative to this directory.
+
+--time::
+ Only analyze samples within given time window: <start>,<stop>. Times
+ have the format seconds.microseconds. If start is not given (i.e., time
+ string is ',x.y') then analysis starts at the beginning of the file. If
+ stop time is not given (i.e, time string is 'x.y,') then analysis goes
+ to end of file.
+
SEE ALSO
--------
linkperf:perf-record[1]
diff --git a/tools/perf/builtin-kwork.c b/tools/perf/builtin-kwork.c
index 245e4aae258e..dc5fca1863f6 100644
--- a/tools/perf/builtin-kwork.c
+++ b/tools/perf/builtin-kwork.c
@@ -35,10 +35,12 @@
#define PRINT_TIMESTAMP_WIDTH 17
#define PRINT_KWORK_NAME_WIDTH 30
#define RPINT_DECIMAL_WIDTH 3
+#define PRINT_BRACKETPAIR_WIDTH 2
#define PRINT_TIME_UNIT_SEC_WIDTH 2
#define PRINT_TIME_UNIT_MESC_WIDTH 3
#define PRINT_RUNTIME_HEADER_WIDTH (PRINT_RUNTIME_WIDTH + PRINT_TIME_UNIT_MESC_WIDTH)
#define PRINT_LATENCY_HEADER_WIDTH (PRINT_LATENCY_WIDTH + PRINT_TIME_UNIT_MESC_WIDTH)
+#define PRINT_TIMEHIST_CPU_WIDTH (PRINT_CPU_WIDTH + PRINT_BRACKETPAIR_WIDTH)
#define PRINT_TIMESTAMP_HEADER_WIDTH (PRINT_TIMESTAMP_WIDTH + PRINT_TIME_UNIT_SEC_WIDTH)

struct sort_dimension {
@@ -575,6 +577,185 @@ static int latency_entry_event(struct perf_kwork *kwork,
return 0;
}

+static void timehist_save_callchain(struct perf_kwork *kwork,
+ struct perf_sample *sample,
+ struct evsel *evsel,
+ struct machine *machine)
+{
+ struct symbol *sym;
+ struct thread *thread;
+ struct callchain_cursor_node *node;
+ struct callchain_cursor *cursor = &callchain_cursor;
+
+ if (!kwork->show_callchain || sample->callchain == NULL)
+ return;
+
+ /* want main thread for process - has maps */
+ thread = machine__findnew_thread(machine, sample->pid, sample->pid);
+ if (thread == NULL) {
+ pr_debug("Failed to get thread for pid %d\n", sample->pid);
+ return;
+ }
+
+ if (thread__resolve_callchain(thread, cursor, evsel, sample,
+ NULL, NULL, kwork->max_stack + 2) != 0) {
+ pr_debug("Failed to resolve callchain, skipping\n");
+ goto out_put;
+ }
+
+ callchain_cursor_commit(cursor);
+
+ while (true) {
+ node = callchain_cursor_current(cursor);
+ if (node == NULL)
+ break;
+
+ sym = node->ms.sym;
+ if (sym) {
+ if (!strcmp(sym->name, "__softirqentry_text_start") ||
+ !strcmp(sym->name, "__do_softirq"))
+ sym->ignore = 1;
+ }
+
+ callchain_cursor_advance(cursor);
+ }
+
+out_put:
+ thread__put(thread);
+}
+
+static void timehist_print_event(struct perf_kwork *kwork,
+ struct kwork_work *work,
+ struct kwork_atom *atom,
+ struct perf_sample *sample,
+ struct addr_location *al)
+{
+ char entrytime[32], exittime[32];
+ char kwork_name[PRINT_KWORK_NAME_WIDTH];
+
+ /*
+ * runtime start
+ */
+ timestamp__scnprintf_usec(atom->time,
+ entrytime, sizeof(entrytime));
+ printf(" %*s ", PRINT_TIMESTAMP_WIDTH, entrytime);
+
+ /*
+ * runtime end
+ */
+ timestamp__scnprintf_usec(sample->time,
+ exittime, sizeof(exittime));
+ printf(" %*s ", PRINT_TIMESTAMP_WIDTH, exittime);
+
+ /*
+ * cpu
+ */
+ printf(" [%0*d] ", PRINT_CPU_WIDTH, work->cpu);
+
+ /*
+ * kwork name
+ */
+ if (work->class && work->class->work_name) {
+ work->class->work_name(work, kwork_name,
+ PRINT_KWORK_NAME_WIDTH);
+ printf(" %-*s ", PRINT_KWORK_NAME_WIDTH, kwork_name);
+ } else
+ printf(" %-*s ", PRINT_KWORK_NAME_WIDTH, "");
+
+ /*
+ *runtime
+ */
+ printf(" %*.*f ",
+ PRINT_RUNTIME_WIDTH, RPINT_DECIMAL_WIDTH,
+ (double)(sample->time - atom->time) / NSEC_PER_MSEC);
+
+ /*
+ * delaytime
+ */
+ if (atom->prev != NULL) {
+ printf(" %*.*f ", PRINT_LATENCY_WIDTH, RPINT_DECIMAL_WIDTH,
+ (double)(atom->time - atom->prev->time) / NSEC_PER_MSEC);
+ } else
+ printf(" %*s ", PRINT_LATENCY_WIDTH, " ");
+
+ /*
+ * callchain
+ */
+ if (kwork->show_callchain) {
+ printf(" ");
+ sample__fprintf_sym(sample, al, 0,
+ EVSEL__PRINT_SYM | EVSEL__PRINT_ONELINE |
+ EVSEL__PRINT_CALLCHAIN_ARROW |
+ EVSEL__PRINT_SKIP_IGNORED,
+ &callchain_cursor, symbol_conf.bt_stop_list,
+ stdout);
+ }
+
+ printf("\n");
+}
+
+static int timehist_raise_event(struct perf_kwork *kwork,
+ struct kwork_class *class,
+ struct evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ return work_push_atom(kwork, class, KWORK_TRACE_RAISE,
+ KWORK_TRACE_MAX, evsel, sample,
+ machine, NULL);
+}
+
+static int timehist_entry_event(struct perf_kwork *kwork,
+ struct kwork_class *class,
+ struct evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ int ret;
+ struct kwork_work *work = NULL;
+
+ ret = work_push_atom(kwork, class, KWORK_TRACE_ENTRY,
+ KWORK_TRACE_RAISE, evsel, sample,
+ machine, &work);
+ if (ret)
+ return ret;
+
+ if (work != NULL)
+ timehist_save_callchain(kwork, sample, evsel, machine);
+
+ return 0;
+}
+
+static int timehist_exit_event(struct perf_kwork *kwork,
+ struct kwork_class *class,
+ struct evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ struct kwork_atom *atom = NULL;
+ struct kwork_work *work = NULL;
+ struct addr_location al;
+
+ if (machine__resolve(machine, &al, sample) < 0) {
+ pr_debug("Problem processing event, skipping it\n");
+ return -1;
+ }
+
+ atom = work_pop_atom(kwork, class, KWORK_TRACE_EXIT,
+ KWORK_TRACE_ENTRY, evsel, sample,
+ machine, &work);
+ if (work == NULL)
+ return -1;
+
+ if (atom != NULL) {
+ work->nr_atoms++;
+ timehist_print_event(kwork, work, atom, sample, &al);
+ atom_del(atom);
+ }
+
+ return 0;
+}
+
static struct kwork_class kwork_irq;
static int process_irq_handler_entry_event(struct perf_tool *tool,
struct evsel *evsel,
@@ -1006,6 +1187,42 @@ static int report_print_header(struct perf_kwork *kwork)
return ret;
}

+static void timehist_print_header(void)
+{
+ /*
+ * header row
+ */
+ printf(" %-*s %-*s %-*s %-*s %-*s %-*s\n",
+ PRINT_TIMESTAMP_WIDTH, "Runtime start",
+ PRINT_TIMESTAMP_WIDTH, "Runtime end",
+ PRINT_TIMEHIST_CPU_WIDTH, "Cpu",
+ PRINT_KWORK_NAME_WIDTH, "Kwork name",
+ PRINT_RUNTIME_WIDTH, "Runtime",
+ PRINT_RUNTIME_WIDTH, "Delaytime");
+
+ /*
+ * units row
+ */
+ printf(" %-*s %-*s %-*s %-*s %-*s %-*s\n",
+ PRINT_TIMESTAMP_WIDTH, "",
+ PRINT_TIMESTAMP_WIDTH, "",
+ PRINT_TIMEHIST_CPU_WIDTH, "",
+ PRINT_KWORK_NAME_WIDTH, "(TYPE)NAME:NUM",
+ PRINT_RUNTIME_WIDTH, "(msec)",
+ PRINT_RUNTIME_WIDTH, "(msec)");
+
+ /*
+ * separator
+ */
+ printf(" %.*s %.*s %.*s %.*s %.*s %.*s\n",
+ PRINT_TIMESTAMP_WIDTH, graph_dotted_line,
+ PRINT_TIMESTAMP_WIDTH, graph_dotted_line,
+ PRINT_TIMEHIST_CPU_WIDTH, graph_dotted_line,
+ PRINT_KWORK_NAME_WIDTH, graph_dotted_line,
+ PRINT_RUNTIME_WIDTH, graph_dotted_line,
+ PRINT_RUNTIME_WIDTH, graph_dotted_line);
+}
+
static void print_summary(struct perf_kwork *kwork)
{
u64 time = kwork->timeend - kwork->timestart;
@@ -1101,6 +1318,7 @@ static int perf_kwork__check_config(struct perf_kwork *kwork,
struct perf_session *session)
{
int ret;
+ struct evsel *evsel;
struct kwork_class *class;

static struct trace_kwork_handler report_ops = {
@@ -1111,6 +1329,11 @@ static int perf_kwork__check_config(struct perf_kwork *kwork,
.raise_event = latency_raise_event,
.entry_event = latency_entry_event,
};
+ static struct trace_kwork_handler timehist_ops = {
+ .raise_event = timehist_raise_event,
+ .entry_event = timehist_entry_event,
+ .exit_event = timehist_exit_event,
+ };

switch (kwork->report) {
case KWORK_REPORT_RUNTIME:
@@ -1119,6 +1342,9 @@ static int perf_kwork__check_config(struct perf_kwork *kwork,
case KWORK_REPORT_LATENCY:
kwork->tp_handler = &latency_ops;
break;
+ case KWORK_REPORT_TIMEHIST:
+ kwork->tp_handler = &timehist_ops;
+ break;
default:
pr_debug("Invalid report type %d\n", kwork->report);
return -1;
@@ -1148,6 +1374,14 @@ static int perf_kwork__check_config(struct perf_kwork *kwork,
}
}

+ list_for_each_entry(evsel, &session->evlist->core.entries, core.node) {
+ if (kwork->show_callchain && !evsel__has_callchain(evsel)) {
+ pr_debug("Samples do not have callchains\n");
+ kwork->show_callchain = 0;
+ symbol_conf.use_callchain = 0;
+ }
+ }
+
return 0;
}

@@ -1181,6 +1415,9 @@ static int perf_kwork__read_events(struct perf_kwork *kwork)
goto out_delete;
}

+ if (kwork->report == KWORK_REPORT_TIMEHIST)
+ timehist_print_header();
+
ret = perf_session__process_events(session);
if (ret) {
pr_debug("Failed to process events, error %d\n", ret);
@@ -1274,6 +1511,31 @@ static int perf_kwork__process_tracepoint_sample(struct perf_tool *tool,
return err;
}

+static int perf_kwork__timehist(struct perf_kwork *kwork)
+{
+ /*
+ * event handlers for timehist option
+ */
+ kwork->tool.comm = perf_event__process_comm;
+ kwork->tool.exit = perf_event__process_exit;
+ kwork->tool.fork = perf_event__process_fork;
+ kwork->tool.attr = perf_event__process_attr;
+ kwork->tool.tracing_data = perf_event__process_tracing_data;
+ kwork->tool.build_id = perf_event__process_build_id;
+ kwork->tool.ordered_events = true;
+ kwork->tool.ordering_requires_timestamps = true;
+ symbol_conf.use_callchain = kwork->show_callchain;
+
+ if (symbol__validate_sym_arguments()) {
+ pr_err("Failed to validate sym arguments\n");
+ return -1;
+ }
+
+ setup_pager();
+
+ return perf_kwork__read_events(kwork);
+}
+
static void setup_event_list(struct perf_kwork *kwork,
const struct option *options,
const char * const usage_msg[])
@@ -1391,6 +1653,8 @@ int cmd_kwork(int argc, const char **argv)
.event_list_str = NULL,
.summary = false,
.sort_order = NULL,
+ .show_callchain = false,
+ .max_stack = 5,

.timestart = 0,
.timeend = 0,
@@ -1439,6 +1703,27 @@ int cmd_kwork(int argc, const char **argv)
"input file name"),
OPT_PARENT(kwork_options)
};
+ const struct option timehist_options[] = {
+ OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
+ "file", "vmlinux pathname"),
+ OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
+ "file", "kallsyms pathname"),
+ OPT_BOOLEAN('g', "call-graph", &kwork.show_callchain,
+ "Display call chains if present"),
+ OPT_UINTEGER(0, "max-stack", &kwork.max_stack,
+ "Maximum number of functions to display backtrace."),
+ OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+ "Look for files with symbols relative to this directory"),
+ OPT_STRING(0, "time", &kwork.time_str, "str",
+ "Time span for analysis (start,stop)"),
+ OPT_STRING('C', "cpu", &kwork.cpu_list, "cpu",
+ "list of cpus to profile"),
+ OPT_STRING('n', "name", &kwork.profile_name, "name",
+ "event name to profile"),
+ OPT_STRING('i', "input", &input_name, "file",
+ "input file name"),
+ OPT_PARENT(kwork_options)
+ };
const char *kwork_usage[] = {
NULL,
NULL
@@ -1451,8 +1736,12 @@ int cmd_kwork(int argc, const char **argv)
"perf kwork latency [<options>]",
NULL
};
+ const char * const timehist_usage[] = {
+ "perf kwork timehist [<options>]",
+ NULL
+ };
const char *const kwork_subcommands[] = {
- "record", "report", "latency", NULL
+ "record", "report", "latency", "timehist", NULL
};

argc = parse_options_subcommand(argc, argv, kwork_options,
@@ -1486,6 +1775,14 @@ int cmd_kwork(int argc, const char **argv)
kwork.report = KWORK_REPORT_LATENCY;
setup_sorting(&kwork, latency_options, latency_usage);
return perf_kwork__report(&kwork);
+ } else if (strlen(argv[0]) > 2 && strstarts("timehist", argv[0])) {
+ if (argc > 1) {
+ argc = parse_options(argc, argv, timehist_options, timehist_usage, 0);
+ if (argc)
+ usage_with_options(timehist_usage, timehist_options);
+ }
+ kwork.report = KWORK_REPORT_TIMEHIST;
+ return perf_kwork__timehist(&kwork);
} else
usage_with_options(kwork_usage, kwork_options);

diff --git a/tools/perf/util/kwork.h b/tools/perf/util/kwork.h
index e540373ab14e..6a06194304b8 100644
--- a/tools/perf/util/kwork.h
+++ b/tools/perf/util/kwork.h
@@ -22,6 +22,7 @@ enum kwork_class_type {
enum kwork_report_type {
KWORK_REPORT_RUNTIME,
KWORK_REPORT_LATENCY,
+ KWORK_REPORT_TIMEHIST,
};

enum kwork_trace_type {
@@ -200,6 +201,8 @@ struct perf_kwork {
*/
bool summary;
const char *sort_order;
+ bool show_callchain;
+ unsigned int max_stack;

/*
* statistics
--
2.30.GIT