// SPDX-License-Identifier: GPL-2.0
/*
* OS Noise Tracer: computes the OS Noise suffered by a running thread.
*
* Based on "hwlat_detector" tracer by:
* Copyright (C) 2008-2009 Jon Masters, Red Hat, Inc. <jcm@redhat.com>
* Copyright (C) 2013-2016 Steven Rostedt, Red Hat, Inc. <srostedt@redhat.com>
* With feedback from Clark Williams <williams@redhat.com>
*
* And also based on the rtsl tracer presented on:
* DE OLIVEIRA, Daniel Bristot, et al. Demystifying the real-time linux
* scheduling latency. In: 32nd Euromicro Conference on Real-Time Systems
* (ECRTS 2020). Schloss Dagstuhl-Leibniz-Zentrum fur Informatik, 2020.
*
* Copyright (C) 2021 Daniel Bristot de Oliveira, Red Hat, Inc. <bristot@redhat.com>
*/
#include <linux/kthread.h>
#include <linux/tracefs.h>
#include <linux/uaccess.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <linux/sched/clock.h>
#include <linux/sched.h>
#include "trace.h"
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/trace/irq_vectors.h>
#undef TRACE_INCLUDE_PATH
#undef TRACE_INCLUDE_FILE
#endif /* CONFIG_X86_LOCAL_APIC */
#include <trace/events/irq.h>
#include <trace/events/sched.h>
#define CREATE_TRACE_POINTS
#include <trace/events/osnoise.h>
static struct trace_array *osnoise_trace;
/*
* Default values.
*/
#define BANNER "osnoise: "
#define DEFAULT_SAMPLE_PERIOD 1000000 /* 1s */
#define DEFAULT_SAMPLE_RUNTIME 1000000 /* 1s */
/*
* NMI runtime info.
*/
struct osn_nmi {
u64 count;
u64 delta_start;
};
/*
* IRQ runtime info.
*/
struct osn_irq {
u64 count;
u64 arrival_time;
u64 delta_start;
};
/*
* sofirq runtime info.
*/
struct osn_softirq {
u64 count;
u64 arrival_time;
u64 delta_start;
};
/*
* thread runtime info.
*/
struct osn_thread {
u64 count;
u64 arrival_time;
u64 delta_start;
};
/*
* Runtime information: this structure saves the runtime information used by
* one sampling thread.
*/
struct osnoise_variables {
struct task_struct *kthread;
bool sampling;
pid_t pid;
struct osn_nmi nmi;
struct osn_irq irq;
struct osn_softirq softirq;
struct osn_thread thread;
local_t int_counter;
};
/*
* Per-cpu runtime information.
*/
DEFINE_PER_CPU(struct osnoise_variables, per_cpu_osnoise_var);
/*
* this_cpu_osn_var - Return the per-cpu osnoise_variables on its relative CPU
*/
static inline struct osnoise_variables *this_cpu_osn_var(void)
{
return this_cpu_ptr(&per_cpu_osnoise_var);
}
/*
* osn_var_reset - Reset the values of the given osnoise_variables
*/
static inline void osn_var_reset(struct osnoise_variables *osn_var)
{
/*
* So far, all the values are initialized as 0, so
