// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2023 Red Hat Inc, Daniel Bristot de Oliveira <[email protected]>
*/
#include <stdlib.h>
#include <errno.h>
#include "utils.h"
#include "osnoise.h"
#include "timerlat.h"
#include <unistd.h>
enum timelat_state {
TIMERLAT_INIT = 0,
TIMERLAT_WAITING_IRQ,
TIMERLAT_WAITING_THREAD,
};
/* Used to fill spaces in the output */
static const char *spaces = " ";
#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_thread_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.
*/
static 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, " %24s %.*s %9.2f us\n",
"nmi",
24, spaces,
ns_to_usf(duration));
return 0;
}
taa_data->thread_nmi_sum += duration;
trace_seq_printf(taa_data->nmi_seq, " %24s %.*s %9.2f us\n",
"nmi",
24, spaces, 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, " %24s:%-3llu %.*s %9.2f us\n",
desc, vector,
15, spaces,
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;
/*
* We are dealing with two different clock sources: the
* external clock source that timerlat uses as a reference
* and the clock used by the tracer. There are also two
* moments: the time reading the clock and the timer in
* which the event is placed in the buffer (the trace
* event timestamp). If the processor is slow or there
* is some hardware noise, the difference between the
* timestamp and the external clock read can be longer
* than the IRQ handler delay, resulting in a negative
* time. If so, set IRQ start delay as 0. In the end,
* it is less relevant than the noise.
*/
if (expected_start < taa_data->timer_irq_start_time)
taa_data->timer_irq_start_delay = taa_data->timer_irq_start_time - expected_start;
else
taa_data->timer_irq_start_delay = 0;
/*
* 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 %.*s %9.2f us\n",
desc, vector,
24, spaces,
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, " %24s:%-3llu %.*s %9.2f us\n",
softirq_name[vector], vector,
24, spaces,
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, " %24s:%-12llu %.*s %9.2f us\n",
comm, pid,
15, spaces,
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, " %.*s -> %s\n",
14, spaces, 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)
{
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.
*
* TODO: Add a list of previous IRQ, and then run the list backwards.
*/
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) {
if (taa_data->prev_irq_timstamp < taa_data->timer_irq_start_time)
printf(" Previous IRQ interference: %.*s up to %9.2f us\n",
16, spaces,
ns_to_usf(taa_data->prev_irq_duration));
}
/*
* The delay that the IRQ suffered before starting.
*/
printf(" IRQ handler delay: %.*s %16s %9.2f us (%.2f %%)\n", 16, spaces,
(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: %.*s %9.2f us\n", 40, spaces,
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(" %.*s %24s:%-9llu\n", 6, spaces, 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: %.*s %9.2f us (%.2f %%)\n",
30, spaces,
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: %.*s %9.2f us (%.2f %%)\n", 36, spaces,
ns_to_usf(taa_data->thread_blocking_duration),
ns_to_per(total, taa_data->thread_blocking_duration));
printf(" %.*s %24s:%-9llu %.*s %9.2f us\n", 6, spaces,
taa_data->run_thread_comm, taa_data->run_thread_pid,
12, spaces, 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 %.*s %9.2f us (%.2f %%)\n", 36, spaces,
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 %.*s %9.2f us (%.2f %%)\n", 36, spaces,
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 %.*s %9.2f us (%.2f %%)\n", 32, spaces,
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 %.*s %9.2f us (%.2f %%)\n", 33, spaces,
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: %.*s %9.2f us (100%%)\n", irq ? " IRQ" : "Thread",
37, spaces, ns_to_usf(total));
}
static int timerlat_auto_analysis_collect_trace(struct timerlat_aa_context *taa_ctx)
{
struct trace_instance *trace = &taa_ctx->tool->trace;
int retval;
retval = tracefs_iterate_raw_events(trace->tep,
trace->inst,
NULL,
0,
collect_registered_events,
trace);
if (retval < 0) {
err_msg("Error iterating on events\n");
return 0;
}
return 1;
}
/**
* 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;
timerlat_auto_analysis_collect_trace(taa_ctx);
/* 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)
{
tep_unregister_event_handler(tool->trace.tep, -1, "ftrace", "timerlat",
timerlat_aa_handler, tool);
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;
tep_register_event_handler(tool->trace.tep, -1, "ftrace", "timerlat",
timerlat_aa_handler, tool);
/*
* 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 dump_tasks)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
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;
}
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