Message-Id: <1ee073822f6a2cbb33da0c817331d0d4045e837f.1675179318.git.bristot@kernel.org>
Date:   Tue, 31 Jan 2023 16:38:53 +0100
From:   Daniel Bristot de Oliveira <bristot@...nel.org>
To:     Daniel Bristot de Oliveira <bristot@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Jonathan Corbet <corbet@....net>
Cc:     linux-trace-devel@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] rtla/timerlat: Add auto-analysis core

Currently, timerlat displays a summary of the timerlat tracer results
saving the trace if the system hits a stop condition.

While this represented a huge step forward, the root cause was not
that is accessible to non-expert users.

The auto-analysis fulfill this gap by parsing the trace timerlat runs,
printing an intuitive auto-analysis.

Cc: Daniel Bristot de Oliveira <bristot@...nel.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Jonathan Corbet <corbet@....net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@...nel.org>
---
 tools/tracing/rtla/src/timerlat_aa.c | 990 +++++++++++++++++++++++++++
 tools/tracing/rtla/src/timerlat_aa.h |  12 +
 tools/tracing/rtla/src/utils.h       |   3 +
 3 files changed, 1005 insertions(+)
 create mode 100644 tools/tracing/rtla/src/timerlat_aa.c
 create mode 100644 tools/tracing/rtla/src/timerlat_aa.h

diff --git a/tools/tracing/rtla/src/timerlat_aa.c b/tools/tracing/rtla/src/timerlat_aa.c
new file mode 100644
index 000000000000..ec4e0f4b0e6c
--- /dev/null
+++ b/tools/tracing/rtla/src/timerlat_aa.c
@@ -0,0 +1,990 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 Red Hat Inc, Daniel Bristot de Oliveira <bristot@...nel.org>
+ */
+
+#include <stdlib.h>
+#include <errno.h>
+#include "utils.h"
+#include "osnoise.h"
+#include "timerlat.h"
+
+enum timelat_state {
+	TIMERLAT_INIT = 0,
+	TIMERLAT_WAITING_IRQ,
+	TIMERLAT_WAITING_THREAD,
+};
+
+#define MAX_COMM		24
+
+/*
+ * Per-cpu data statistics and data.
+ */
+struct timerlat_aa_data {
+	/* Current CPU state */
+	int			curr_state;
+
+	/* timerlat IRQ latency */
+	unsigned long long	tlat_irq_seqnum;
+	unsigned long long	tlat_irq_latency;
+	unsigned long long	tlat_irq_timstamp;
+
+	/* timerlat Thread latency */
+	unsigned long long	tlat_thread_seqnum;
+	unsigned long long	tlat_thread_latency;
+	unsigned long long	tlat_thread_timstamp;
+
+	/*
+	 * Information about the thread running when the IRQ
+	 * arrived.
+	 *
+	 * This can be blocking or interference, depending on the
+	 * priority of the thread. Assuming timerlat is the highest
+	 * prio, it is blocking. If timerlat has a lower prio, it is
+	 * interference.
+	 * note: "unsigned long long" because they are fetch using tep_get_field_val();
+	 */
+	unsigned long long	run_thread_pid;
+	char			run_thread_comm[MAX_COMM];
+	unsigned long long	thread_blocking_duration;
+	unsigned long long	max_exit_idle_latency;
+
+	/* Information about the timerlat timer irq */
+	unsigned long long	timer_irq_start_time;
+	unsigned long long	timer_irq_start_delay;
+	unsigned long long	timer_irq_duration;
+	unsigned long long	timer_exit_from_idle;
+
+	/*
+	 * Information about the last IRQ before the timerlat irq
+	 * arrived.
+	 *
+	 * If now - timestamp is <= latency, it might have influenced
+	 * in the timerlat irq latency. Otherwise, ignore it.
+	 */
+	unsigned long long	prev_irq_duration;
+	unsigned long long	prev_irq_timstamp;
+
+	/*
+	 * Interference sum.
+	 */
+	unsigned long long	thread_nmi_sum;
+	unsigned long long	thread_irq_sum;
+	unsigned long long	thread_softirq_sum;
+	unsigned long long	thread_thread_sum;
+
+	/*
+	 * Interference task information.
+	 */
+	struct trace_seq	*prev_irqs_seq;
+	struct trace_seq	*nmi_seq;
+	struct trace_seq	*irqs_seq;
+	struct trace_seq	*softirqs_seq;
+	struct trace_seq	*threads_seq;
+	struct trace_seq	*stack_seq;
+
+	/*
+	 * Current thread.
+	 */
+	char			current_comm[MAX_COMM];
+	unsigned long long	current_pid;
+
+	/*
+	 * Is the system running a kworker?
+	 */
+	unsigned long long	kworker;
+	unsigned long long	kworker_func;
+};
+
+/*
+ * The analysis context and system wide view
+ */
+struct timerlat_aa_context {
+	int nr_cpus;
+	int dump_tasks;
+
+	/* per CPU data */
+	struct timerlat_aa_data *taa_data;
+
+	/*
+	 * required to translate function names and register
+	 * events.
+	 */
+	struct osnoise_tool *tool;
+};
+
+/*
+ * The data is stored as a local variable, but accessed via a helper function.
+ *
+ * It could be stored inside the trace context. But every access would
+ * require container_of() + a series of pointers. Do we need it? Not sure.
+ *
+ * For now keep it simple. If needed, store it in the tool, add the *context
+ * as a parameter in timerlat_aa_get_ctx() and do the magic there.
+ */
+static struct timerlat_aa_context *__timerlat_aa_ctx;
+
+static struct timerlat_aa_context *timerlat_aa_get_ctx(void)
+{
+	return __timerlat_aa_ctx;
+}
+
+/*
+ * timerlat_aa_get_data - Get the per-cpu data from the timerlat context
+ */
+static struct timerlat_aa_data
+*timerlat_aa_get_data(struct timerlat_aa_context *taa_ctx, int cpu)
+{
+	return &taa_ctx->taa_data[cpu];
+}
+
+/*
+ * timerlat_aa_irq_latency - Handles timerlat IRQ event
+ */
+static int timerlat_aa_irq_latency(struct timerlat_aa_data *taa_data,
+				   struct trace_seq *s, struct tep_record *record,
+				   struct tep_event *event)
+{
+	/*
+	 * For interference, we start now looking for things that can delay
+	 * the thread.
+	 */
+	taa_data->curr_state = TIMERLAT_WAITING_THREAD;
+	taa_data->tlat_irq_timstamp = record->ts;
+
+	/*
+	 * Zero values.
+	 */
+	taa_data->thread_nmi_sum = 0;
+	taa_data->thread_irq_sum = 0;
+	taa_data->thread_softirq_sum = 0;
+	taa_data->thread_blocking_duration = 0;
+	taa_data->timer_irq_start_time = 0;
+	taa_data->timer_irq_duration = 0;
+	taa_data->timer_exit_from_idle = 0;
+
+	/*
+	 * Zero interference tasks.
+	 */
+	trace_seq_reset(taa_data->nmi_seq);
+	trace_seq_reset(taa_data->irqs_seq);
+	trace_seq_reset(taa_data->softirqs_seq);
+	trace_seq_reset(taa_data->threads_seq);
+
+	/* IRQ latency values */
+	tep_get_field_val(s, event, "timer_latency", record, &taa_data->tlat_irq_latency, 1);
+	tep_get_field_val(s, event, "seqnum", record, &taa_data->tlat_irq_seqnum, 1);
+
+	/* The thread that can cause blocking */
+	tep_get_common_field_val(s, event, "common_pid", record, &taa_data->run_thread_pid, 1);
+
+	/*
+	 * Get exit from idle case.
+	 *
+	 * If it is not idle thread:
+	 */
+	if (taa_data->run_thread_pid)
+		return 0;
+
+	/*
+	 * if the latency is shorter than the known exit from idle:
+	 */
+	if (taa_data->tlat_irq_latency < taa_data->max_exit_idle_latency)
+		return 0;
+
+	/*
+	 * To be safe, ignore the cases in which an IRQ/NMI could have
+	 * interfered with the timerlat IRQ.
+	 */
+	if (taa_data->tlat_irq_timstamp - taa_data->tlat_irq_latency
+	    < taa_data->prev_irq_timstamp + taa_data->prev_irq_duration)
+		return 0;
+
+	taa_data->max_exit_idle_latency = taa_data->tlat_irq_latency;
+
+	return 0;
+}
+
+/*
+ * timerlat_aa_thread_latency - Handles timerlat thread event
+ */
+static int timerlat_aa_thread_latency(struct timerlat_aa_data *taa_data,
+				      struct trace_seq *s, struct tep_record *record,
+				      struct tep_event *event)
+{
+	/*
+	 * For interference, we start now looking for things that can delay
+	 * the IRQ of the next cycle.
+	 */
+	taa_data->curr_state = TIMERLAT_WAITING_IRQ;
+	taa_data->tlat_thread_timstamp = record->ts;
+
+	/* Thread latency values */
+	tep_get_field_val(s, event, "timer_latency", record, &taa_data->tlat_thread_latency, 1);
+	tep_get_field_val(s, event, "seqnum", record, &taa_data->tlat_thread_seqnum, 1);
+
+	return 0;
+}
+
+/*
+ * timerlat_aa_handler - Handle timerlat events
+ *
+ * This function is called to handle timerlat events recording statistics.
+ *
+ * Returns 0 on success, -1 otherwise.
+ */
+int timerlat_aa_handler(struct trace_seq *s, struct tep_record *record,
+			struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+	unsigned long long thread;
+
+	if (!taa_data)
+		return -1;
+
+	tep_get_field_val(s, event, "context", record, &thread, 1);
+	if (!thread)
+		return timerlat_aa_irq_latency(taa_data, s, record, event);
+	else
+		return timerlat_aa_thread_latency(taa_data, s, record, event);
+}
+
+/*
+ * timerlat_aa_nmi_handler - Handles NMI noise
+ *
+ * It is used to collect information about interferences from NMI. It is
+ * hooked to the osnoise:nmi_noise event.
+ */
+static int timerlat_aa_nmi_handler(struct trace_seq *s, struct tep_record *record,
+				   struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+	unsigned long long duration;
+	unsigned long long start;
+
+	tep_get_field_val(s, event, "duration", record, &duration, 1);
+	tep_get_field_val(s, event, "start", record, &start, 1);
+
+	if (taa_data->curr_state == TIMERLAT_WAITING_IRQ) {
+		taa_data->prev_irq_duration = duration;
+		taa_data->prev_irq_timstamp = start;
+
+		trace_seq_reset(taa_data->prev_irqs_seq);
+		trace_seq_printf(taa_data->prev_irqs_seq, "\t%24s	\t\t\t%9.2f us\n",
+			 "nmi", ns_to_usf(duration));
+		return 0;
+	}
+
+	taa_data->thread_nmi_sum += duration;
+	trace_seq_printf(taa_data->nmi_seq, "	%24s	\t\t\t%9.2f us\n",
+		 "nmi", ns_to_usf(duration));
+
+	return 0;
+}
+
+/*
+ * timerlat_aa_irq_handler - Handles IRQ noise
+ *
+ * It is used to collect information about interferences from IRQ. It is
+ * hooked to the osnoise:irq_noise event.
+ *
+ * It is a little bit more complex than the other because it measures:
+ *	- The IRQs that can delay the timer IRQ before it happened.
+ *	- The Timerlat IRQ handler
+ *	- The IRQs that happened between the timerlat IRQ and the timerlat thread
+ *	  (IRQ interference).
+ */
+static int timerlat_aa_irq_handler(struct trace_seq *s, struct tep_record *record,
+				   struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+	unsigned long long expected_start;
+	unsigned long long duration;
+	unsigned long long vector;
+	unsigned long long start;
+	char *desc;
+	int val;
+
+	tep_get_field_val(s, event, "duration", record, &duration, 1);
+	tep_get_field_val(s, event, "start", record, &start, 1);
+	tep_get_field_val(s, event, "vector", record, &vector, 1);
+	desc = tep_get_field_raw(s, event, "desc", record, &val, 1);
+
+	/*
+	 * Before the timerlat IRQ.
+	 */
+	if (taa_data->curr_state == TIMERLAT_WAITING_IRQ) {
+		taa_data->prev_irq_duration = duration;
+		taa_data->prev_irq_timstamp = start;
+
+		trace_seq_reset(taa_data->prev_irqs_seq);
+		trace_seq_printf(taa_data->prev_irqs_seq, "\t%24s:%-3llu	\t\t%9.2f us\n",
+				 desc, vector, ns_to_usf(duration));
+		return 0;
+	}
+
+	/*
+	 * The timerlat IRQ: taa_data->timer_irq_start_time is zeroed at
+	 * the timerlat irq handler.
+	 */
+	if (!taa_data->timer_irq_start_time) {
+		expected_start = taa_data->tlat_irq_timstamp - taa_data->tlat_irq_latency;
+
+		taa_data->timer_irq_start_time = start;
+		taa_data->timer_irq_duration = duration;
+
+		taa_data->timer_irq_start_delay = taa_data->timer_irq_start_time - expected_start;
+
+		/*
+		 * not exit from idle.
+		 */
+		if (taa_data->run_thread_pid)
+			return 0;
+
+		if (expected_start > taa_data->prev_irq_timstamp + taa_data->prev_irq_duration)
+			taa_data->timer_exit_from_idle = taa_data->timer_irq_start_delay;
+
+		return 0;
+	}
+
+	/*
+	 * IRQ interference.
+	 */
+	taa_data->thread_irq_sum += duration;
+	trace_seq_printf(taa_data->irqs_seq, "	%24s:%-3llu	\t	%9.2f us\n",
+			 desc, vector, ns_to_usf(duration));
+
+	return 0;
+}
+
+static char *softirq_name[] = { "HI", "TIMER",	"NET_TX", "NET_RX", "BLOCK",
+				"IRQ_POLL", "TASKLET", "SCHED", "HRTIMER", "RCU" };
+
+
+/*
+ * timerlat_aa_softirq_handler - Handles Softirq noise
+ *
+ * It is used to collect information about interferences from Softirq. It is
+ * hooked to the osnoise:softirq_noise event.
+ *
+ * It is only printed in the non-rt kernel, as softirqs become thread on RT.
+ */
+static int timerlat_aa_softirq_handler(struct trace_seq *s, struct tep_record *record,
+				       struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+	unsigned long long duration;
+	unsigned long long vector;
+	unsigned long long start;
+
+	if (taa_data->curr_state == TIMERLAT_WAITING_IRQ)
+		return 0;
+
+	tep_get_field_val(s, event, "duration", record, &duration, 1);
+	tep_get_field_val(s, event, "start", record, &start, 1);
+	tep_get_field_val(s, event, "vector", record, &vector, 1);
+
+	taa_data->thread_softirq_sum += duration;
+
+	trace_seq_printf(taa_data->softirqs_seq, "\t%24s:%-3llu	\t	%9.2f us\n",
+			 softirq_name[vector], vector, ns_to_usf(duration));
+	return 0;
+}
+
+/*
+ * timerlat_aa_softirq_handler - Handles thread noise
+ *
+ * It is used to collect information about interferences from threads. It is
+ * hooked to the osnoise:thread_noise event.
+ *
+ * Note: if you see thread noise, your timerlat thread was not the highest prio one.
+ */
+static int timerlat_aa_thread_handler(struct trace_seq *s, struct tep_record *record,
+				      struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+	unsigned long long duration;
+	unsigned long long start;
+	unsigned long long pid;
+	const char *comm;
+	int val;
+
+	if (taa_data->curr_state == TIMERLAT_WAITING_IRQ)
+		return 0;
+
+	tep_get_field_val(s, event, "duration", record, &duration, 1);
+	tep_get_field_val(s, event, "start", record, &start, 1);
+
+	tep_get_common_field_val(s, event, "common_pid", record, &pid, 1);
+	comm = tep_get_field_raw(s, event, "comm", record, &val, 1);
+
+	if (pid == taa_data->run_thread_pid && !taa_data->thread_blocking_duration) {
+		taa_data->thread_blocking_duration = duration;
+
+		if (comm)
+			strncpy(taa_data->run_thread_comm, comm, MAX_COMM);
+		else
+			sprintf(taa_data->run_thread_comm, "<...>");
+
+	} else {
+		taa_data->thread_thread_sum += duration;
+
+		trace_seq_printf(taa_data->threads_seq, "\t%24s:%-3llu	\t\t%9.2f us\n",
+			 comm, pid, ns_to_usf(duration));
+	}
+
+	return 0;
+}
+
+/*
+ * timerlat_aa_stack_handler - Handles timerlat IRQ stack trace
+ *
+ * Saves and parse the stack trace generated by the timerlat IRQ.
+ */
+static int timerlat_aa_stack_handler(struct trace_seq *s, struct tep_record *record,
+			      struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+	unsigned long *caller;
+	const char *function;
+	int val, i;
+
+	trace_seq_reset(taa_data->stack_seq);
+
+	trace_seq_printf(taa_data->stack_seq, "    Blocking thread stack trace\n");
+	caller = tep_get_field_raw(s, event, "caller", record, &val, 1);
+	if (caller) {
+		for (i = 0; ; i++) {
+			function = tep_find_function(taa_ctx->tool->trace.tep, caller[i]);
+			if (!function)
+				break;
+			trace_seq_printf(taa_data->stack_seq, "\t\t-> %s\n", function);
+		}
+	}
+	return 0;
+}
+
+/*
+ * timerlat_aa_sched_switch_handler - Tracks the current thread running on the CPU
+ *
+ * Handles the sched:sched_switch event to trace the current thread running on the
+ * CPU. It is used to display the threads running on the other CPUs when the trace
+ * stops.
+ */
+static int timerlat_aa_sched_switch_handler(struct trace_seq *s, struct tep_record *record,
+					    struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+	const char *comm;
+	int val;
+
+	tep_get_field_val(s, event, "next_pid", record, &taa_data->current_pid, 1);
+	comm = tep_get_field_raw(s, event, "next_comm", record, &val, 1);
+
+	strncpy(taa_data->current_comm, comm, MAX_COMM);
+
+	/*
+	 * If this was a kworker, clean the last kworkers that ran.
+	 */
+	taa_data->kworker = 0;
+	taa_data->kworker_func = 0;
+
+	return 0;
+}
+
+/*
+ * timerlat_aa_kworker_start_handler - Tracks a kworker running on the CPU
+ *
+ * Handles workqueue:workqueue_execute_start event, keeping track of
+ * the job that a kworker could be doing in the CPU.
+ *
+ * We already catch problems of hardware related latencies caused by work queues
+ * running driver code that causes hardware stall. For example, with DRM drivers.
+ */
+static int timerlat_aa_kworker_start_handler(struct trace_seq *s, struct tep_record *record,
+					     struct tep_event *event, void *context)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	struct timerlat_aa_data *taa_data = timerlat_aa_get_data(taa_ctx, record->cpu);
+
+	tep_get_field_val(s, event, "work", record, &taa_data->kworker, 1);
+	tep_get_field_val(s, event, "function", record, &taa_data->kworker_func, 1);
+	return 0;
+}
+
+/*
+ * timerlat_thread_analysis - Prints the analysis of a CPU that hit a stop tracing
+ *
+ * This is the core of the analysis.
+ */
+static void timerlat_thread_analysis(struct timerlat_aa_data *taa_data, int cpu,
+				     int irq_thresh, int thread_thresh)
+{
+	unsigned long long exp_irq_ts;
+	int total;
+	int irq;
+
+	/*
+	 * IRQ latency or Thread latency?
+	 */
+	if (taa_data->tlat_irq_seqnum > taa_data->tlat_thread_seqnum) {
+		irq = 1;
+		total = taa_data->tlat_irq_latency;
+	} else {
+		irq = 0;
+		total = taa_data->tlat_thread_latency;
+	}
+
+	/*
+	 * Expected IRQ arrival time using the trace clock as the base.
+	 */
+	exp_irq_ts = taa_data->timer_irq_start_time - taa_data->timer_irq_start_delay;
+
+	if (exp_irq_ts < taa_data->prev_irq_timstamp + taa_data->prev_irq_duration)
+		printf("  Previous IRQ interference:	\t	up to %9.2f us",
+			ns_to_usf(taa_data->prev_irq_duration));
+
+	/*
+	 * The delay that the IRQ suffered before starting.
+	 */
+	printf("  IRQ handler delay:		%16s	%9.2f us (%.2f %%)\n",
+		(ns_to_usf(taa_data->timer_exit_from_idle) > 10) ? "(exit from idle)" : "",
+		ns_to_usf(taa_data->timer_irq_start_delay),
+		ns_to_per(total, taa_data->timer_irq_start_delay));
+
+	/*
+	 * Timerlat IRQ.
+	 */
+	printf("  IRQ latency:	\t\t\t\t	%9.2f us\n",
+		ns_to_usf(taa_data->tlat_irq_latency));
+
+	if (irq) {
+		/*
+		 * If the trace stopped due to IRQ, the other events will not happen
+		 * because... the trace stopped :-).
+		 *
+		 * That is all folks, the stack trace was printed before the stop,
+		 * so it will be displayed, it is the key.
+		 */
+		printf("  Blocking thread:\n");
+		printf("	%24s:%-9llu\n",
+			taa_data->run_thread_comm, taa_data->run_thread_pid);
+	} else  {
+		/*
+		 * The duration of the IRQ handler that handled the timerlat IRQ.
+		 */
+		printf("  Timerlat IRQ duration:	\t\t	%9.2f us (%.2f %%)\n",
+			ns_to_usf(taa_data->timer_irq_duration),
+			ns_to_per(total, taa_data->timer_irq_duration));
+
+		/*
+		 * The amount of time that the current thread postponed the scheduler.
+		 *
+		 * Recalling that it is net from NMI/IRQ/Softirq interference, so there
+		 * is no need to compute values here.
+		 */
+		printf("  Blocking thread:	\t\t\t	%9.2f us (%.2f %%)\n",
+			ns_to_usf(taa_data->thread_blocking_duration),
+			ns_to_per(total, taa_data->thread_blocking_duration));
+
+		printf("	%24s:%-9llu		%9.2f us\n",
+			taa_data->run_thread_comm, taa_data->run_thread_pid,
+			ns_to_usf(taa_data->thread_blocking_duration));
+	}
+
+	/*
+	 * Print the stack trace!
+	 */
+	trace_seq_do_printf(taa_data->stack_seq);
+
+	/*
+	 * NMIs can happen during the IRQ, so they are always possible.
+	 */
+	if (taa_data->thread_nmi_sum)
+		printf("  NMI interference	\t\t\t	%9.2f us (%.2f %%)\n",
+			ns_to_usf(taa_data->thread_nmi_sum),
+			ns_to_per(total, taa_data->thread_nmi_sum));
+
+	/*
+	 * If it is an IRQ latency, the other factors can be skipped.
+	 */
+	if (irq)
+		goto print_total;
+
+	/*
+	 * Prints the interference caused by IRQs to the thread latency.
+	 */
+	if (taa_data->thread_irq_sum) {
+		printf("  IRQ interference	\t\t\t	%9.2f us (%.2f %%)\n",
+			ns_to_usf(taa_data->thread_irq_sum),
+			ns_to_per(total, taa_data->thread_irq_sum));
+
+		trace_seq_do_printf(taa_data->irqs_seq);
+	}
+
+	/*
+	 * Prints the interference caused by Softirqs to the thread latency.
+	 */
+	if (taa_data->thread_softirq_sum) {
+		printf("  Softirq interference	\t\t\t	%9.2f us (%.2f %%)\n",
+			ns_to_usf(taa_data->thread_softirq_sum),
+			ns_to_per(total, taa_data->thread_softirq_sum));
+
+		trace_seq_do_printf(taa_data->softirqs_seq);
+	}
+
+	/*
+	 * Prints the interference caused by other threads to the thread latency.
+	 *
+	 * If this happens, your timerlat is not the highest prio. OK, migration
+	 * thread can happen. But otherwise, you are not measuring the "scheduling
+	 * latency" only, and here is the difference from scheduling latency and
+	 * timer handling latency.
+	 */
+	if (taa_data->thread_thread_sum) {
+		printf("  Thread interference	\t\t\t	%9.2f us (%.2f %%)\n",
+			ns_to_usf(taa_data->thread_thread_sum),
+			ns_to_per(total, taa_data->thread_thread_sum));
+
+		trace_seq_do_printf(taa_data->threads_seq);
+	}
+
+	/*
+	 * Done.
+	 */
+print_total:
+	printf("------------------------------------------------------------------------\n");
+	printf("  %s latency:	\t\t\t	%9.2f us (100%%)\n", irq ? "IRQ" : "Thread",
+		ns_to_usf(total));
+}
+
+/**
+ * timerlat_auto_analysis - Analyze the collected data
+ */
+void timerlat_auto_analysis(int irq_thresh, int thread_thresh)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+	unsigned long long max_exit_from_idle = 0;
+	struct timerlat_aa_data *taa_data;
+	int max_exit_from_idle_cpu;
+	struct tep_handle *tep;
+	int cpu;
+
+	/* bring stop tracing to the ns scale */
+	irq_thresh = irq_thresh * 1000;
+	thread_thresh = thread_thresh * 1000;
+
+	for (cpu = 0; cpu < taa_ctx->nr_cpus; cpu++) {
+		taa_data = timerlat_aa_get_data(taa_ctx, cpu);
+
+		if (irq_thresh && taa_data->tlat_irq_latency >= irq_thresh) {
+			printf("## CPU %d hit stop tracing, analyzing it ##\n", cpu);
+			timerlat_thread_analysis(taa_data, cpu, irq_thresh, thread_thresh);
+		} else if (thread_thresh && (taa_data->tlat_thread_latency) >= thread_thresh) {
+			printf("## CPU %d hit stop tracing, analyzing it ##\n", cpu);
+			timerlat_thread_analysis(taa_data, cpu, irq_thresh, thread_thresh);
+		}
+
+		if (taa_data->max_exit_idle_latency > max_exit_from_idle) {
+			max_exit_from_idle = taa_data->max_exit_idle_latency;
+			max_exit_from_idle_cpu = cpu;
+		}
+
+	}
+
+	if (max_exit_from_idle) {
+		printf("\n");
+		printf("Max timerlat IRQ latency from idle: %.2f us in cpu %d\n",
+			ns_to_usf(max_exit_from_idle), max_exit_from_idle_cpu);
+	}
+	if (!taa_ctx->dump_tasks)
+		return;
+
+	printf("\n");
+	printf("Printing CPU tasks:\n");
+	for (cpu = 0; cpu < taa_ctx->nr_cpus; cpu++) {
+		taa_data = timerlat_aa_get_data(taa_ctx, cpu);
+		tep = taa_ctx->tool->trace.tep;
+
+		printf("    [%.3d] %24s:%llu", cpu, taa_data->current_comm, taa_data->current_pid);
+
+		if (taa_data->kworker_func)
+			printf(" kworker:%s:%s",
+				tep_find_function(tep, taa_data->kworker) ? : "<...>",
+				tep_find_function(tep, taa_data->kworker_func));
+		printf("\n");
+	}
+
+}
+
+/*
+ * timerlat_aa_destroy_seqs - Destroy seq files used to store parsed data
+ */
+static void timerlat_aa_destroy_seqs(struct timerlat_aa_context *taa_ctx)
+{
+	struct timerlat_aa_data *taa_data;
+	int i;
+
+	if (!taa_ctx->taa_data)
+		return;
+
+	for (i = 0; i < taa_ctx->nr_cpus; i++) {
+		taa_data = timerlat_aa_get_data(taa_ctx, i);
+
+		if (taa_data->prev_irqs_seq) {
+			trace_seq_destroy(taa_data->prev_irqs_seq);
+			free(taa_data->prev_irqs_seq);
+		}
+
+		if (taa_data->nmi_seq) {
+			trace_seq_destroy(taa_data->nmi_seq);
+			free(taa_data->nmi_seq);
+		}
+
+		if (taa_data->irqs_seq) {
+			trace_seq_destroy(taa_data->irqs_seq);
+			free(taa_data->irqs_seq);
+		}
+
+		if (taa_data->softirqs_seq) {
+			trace_seq_destroy(taa_data->softirqs_seq);
+			free(taa_data->softirqs_seq);
+		}
+
+		if (taa_data->threads_seq) {
+			trace_seq_destroy(taa_data->threads_seq);
+			free(taa_data->threads_seq);
+		}
+
+		if (taa_data->stack_seq) {
+			trace_seq_destroy(taa_data->stack_seq);
+			free(taa_data->stack_seq);
+		}
+	}
+}
+
+/*
+ * timerlat_aa_init_seqs - Init seq files used to store parsed information
+ *
+ * Instead of keeping data structures to store raw data, use seq files to
+ * store parsed data.
+ *
+ * Allocates and initialize seq files.
+ *
+ * Returns 0 on success, -1 otherwise.
+ */
+static int timerlat_aa_init_seqs(struct timerlat_aa_context *taa_ctx)
+{
+	struct timerlat_aa_data *taa_data;
+	int i;
+
+	for (i = 0; i < taa_ctx->nr_cpus; i++) {
+
+		taa_data = timerlat_aa_get_data(taa_ctx, i);
+
+		taa_data->prev_irqs_seq = calloc(1, sizeof(*taa_data->prev_irqs_seq));
+		if (!taa_data->prev_irqs_seq)
+			goto out_err;
+
+		trace_seq_init(taa_data->prev_irqs_seq);
+
+		taa_data->nmi_seq = calloc(1, sizeof(*taa_data->nmi_seq));
+		if (!taa_data->nmi_seq)
+			goto out_err;
+
+		trace_seq_init(taa_data->nmi_seq);
+
+		taa_data->irqs_seq = calloc(1, sizeof(*taa_data->irqs_seq));
+		if (!taa_data->irqs_seq)
+			goto out_err;
+
+		trace_seq_init(taa_data->irqs_seq);
+
+		taa_data->softirqs_seq = calloc(1, sizeof(*taa_data->softirqs_seq));
+		if (!taa_data->softirqs_seq)
+			goto out_err;
+
+		trace_seq_init(taa_data->softirqs_seq);
+
+		taa_data->threads_seq = calloc(1, sizeof(*taa_data->threads_seq));
+		if (!taa_data->threads_seq)
+			goto out_err;
+
+		trace_seq_init(taa_data->threads_seq);
+
+		taa_data->stack_seq = calloc(1, sizeof(*taa_data->stack_seq));
+		if (!taa_data->stack_seq)
+			goto out_err;
+
+		trace_seq_init(taa_data->stack_seq);
+	}
+
+	return 0;
+
+out_err:
+	timerlat_aa_destroy_seqs(taa_ctx);
+	return -1;
+}
+
+/*
+ * timerlat_aa_unregister_events - Unregister events used in the auto-analysis
+ */
+static void timerlat_aa_unregister_events(struct osnoise_tool *tool, int dump_tasks)
+{
+	tracefs_event_disable(tool->trace.inst, "osnoise", NULL);
+
+	tep_unregister_event_handler(tool->trace.tep, -1, "osnoise", "nmi_noise",
+				     timerlat_aa_nmi_handler, tool);
+
+	tep_unregister_event_handler(tool->trace.tep, -1, "osnoise", "irq_noise",
+				     timerlat_aa_irq_handler, tool);
+
+	tep_unregister_event_handler(tool->trace.tep, -1, "osnoise", "softirq_noise",
+				     timerlat_aa_softirq_handler, tool);
+
+	tep_unregister_event_handler(tool->trace.tep, -1, "osnoise", "thread_noise",
+				     timerlat_aa_thread_handler, tool);
+
+	tep_unregister_event_handler(tool->trace.tep, -1, "ftrace", "kernel_stack",
+				     timerlat_aa_stack_handler, tool);
+	if (!dump_tasks)
+		return;
+
+	tracefs_event_disable(tool->trace.inst, "sched", "sched_switch");
+	tep_unregister_event_handler(tool->trace.tep, -1, "sched", "sched_switch",
+				     timerlat_aa_sched_switch_handler, tool);
+
+	tracefs_event_disable(tool->trace.inst, "workqueue", "workqueue_execute_start");
+	tep_unregister_event_handler(tool->trace.tep, -1, "workqueue", "workqueue_execute_start",
+				     timerlat_aa_kworker_start_handler, tool);
+}
+
+/*
+ * timerlat_aa_register_events - Register events used in the auto-analysis
+ *
+ * Returns 0 on success, -1 otherwise.
+ */
+static int timerlat_aa_register_events(struct osnoise_tool *tool, int dump_tasks)
+{
+	int retval;
+
+	/*
+	 * register auto-analysis handlers.
+	 */
+	retval = tracefs_event_enable(tool->trace.inst, "osnoise", NULL);
+	if (retval < 0 && !errno) {
+		err_msg("Could not find osnoise events\n");
+		goto out_err;
+	}
+
+	tep_register_event_handler(tool->trace.tep, -1, "osnoise", "nmi_noise",
+				   timerlat_aa_nmi_handler, tool);
+
+	tep_register_event_handler(tool->trace.tep, -1, "osnoise", "irq_noise",
+				   timerlat_aa_irq_handler, tool);
+
+	tep_register_event_handler(tool->trace.tep, -1, "osnoise", "softirq_noise",
+				   timerlat_aa_softirq_handler, tool);
+
+	tep_register_event_handler(tool->trace.tep, -1, "osnoise", "thread_noise",
+				   timerlat_aa_thread_handler, tool);
+
+	tep_register_event_handler(tool->trace.tep, -1, "ftrace", "kernel_stack",
+				   timerlat_aa_stack_handler, tool);
+
+	if (!dump_tasks)
+		return 0;
+
+	/*
+	 * Dump task events.
+	 */
+	retval = tracefs_event_enable(tool->trace.inst, "sched", "sched_switch");
+	if (retval < 0 && !errno) {
+		err_msg("Could not find sched_switch\n");
+		goto out_err;
+	}
+
+	tep_register_event_handler(tool->trace.tep, -1, "sched", "sched_switch",
+				   timerlat_aa_sched_switch_handler, tool);
+
+	retval = tracefs_event_enable(tool->trace.inst, "workqueue", "workqueue_execute_start");
+	if (retval < 0 && !errno) {
+		err_msg("Could not find workqueue_execute_start\n");
+		goto out_err;
+	}
+
+	tep_register_event_handler(tool->trace.tep, -1, "workqueue", "workqueue_execute_start",
+				   timerlat_aa_kworker_start_handler, tool);
+
+	return 0;
+
+out_err:
+	timerlat_aa_unregister_events(tool, dump_tasks);
+	return -1;
+}
+
+/**
+ * timerlat_aa_destroy - Destroy timerlat auto-analysis
+ */
+void timerlat_aa_destroy(void)
+{
+	struct timerlat_aa_context *taa_ctx = timerlat_aa_get_ctx();
+
+	if (!taa_ctx)
+		return;
+
+	if (!taa_ctx->taa_data)
+		goto out_ctx;
+
+	timerlat_aa_unregister_events(taa_ctx->tool, taa_ctx->dump_tasks);
+	timerlat_aa_destroy_seqs(taa_ctx);
+	free(taa_ctx->taa_data);
+out_ctx:
+	free(taa_ctx);
+}
+
+/**
+ * timerlat_aa_init - Initialize timerlat auto-analysis
+ *
+ * Returns 0 on success, -1 otherwise.
+ */
+int timerlat_aa_init(struct osnoise_tool *tool, int nr_cpus, int dump_tasks)
+{
+	struct timerlat_aa_context *taa_ctx;
+	int retval;
+
+	taa_ctx = calloc(1, sizeof(*taa_ctx));
+	if (!taa_ctx)
+		return -1;
+
+	__timerlat_aa_ctx = taa_ctx;
+
+	taa_ctx->nr_cpus = nr_cpus;
+	taa_ctx->tool = tool;
+	taa_ctx->dump_tasks = dump_tasks;
+
+	taa_ctx->taa_data = calloc(nr_cpus, sizeof(*taa_ctx->taa_data));
+	if (!taa_ctx->taa_data)
+		goto out_err;
+
+	retval = timerlat_aa_init_seqs(taa_ctx);
+	if (retval)
+		goto out_err;
+
+	retval = timerlat_aa_register_events(tool, dump_tasks);
+	if (retval)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	timerlat_aa_destroy();
+	return -1;
+}
diff --git a/tools/tracing/rtla/src/timerlat_aa.h b/tools/tracing/rtla/src/timerlat_aa.h
new file mode 100644
index 000000000000..d4f6ca7e342a
--- /dev/null
+++ b/tools/tracing/rtla/src/timerlat_aa.h
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 Red Hat Inc, Daniel Bristot de Oliveira <bristot@...nel.org>
+ */
+
+int timerlat_aa_init(struct osnoise_tool *tool, int nr_cpus, int dump_task);
+void timerlat_aa_destroy(void);
+
+int timerlat_aa_handler(struct trace_seq *s, struct tep_record *record,
+			struct tep_event *event, void *context);
+
+void timerlat_auto_analysis(int irq_thresh, int thread_thresh);
diff --git a/tools/tracing/rtla/src/utils.h b/tools/tracing/rtla/src/utils.h
index 5571afd3b549..90e4f52a030b 100644
--- a/tools/tracing/rtla/src/utils.h
+++ b/tools/tracing/rtla/src/utils.h
@@ -56,3 +56,6 @@ struct sched_attr {
 int parse_prio(char *arg, struct sched_attr *sched_param);
 int set_comm_sched_attr(const char *comm_prefix, struct sched_attr *attr);
 int set_cpu_dma_latency(int32_t latency);
+
+#define ns_to_usf(x) (((double)x/1000))
+#define ns_to_per(total, part) ((part * 100) / (double)total)
-- 
2.38.1

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