linux/kernel/trace/preemptirq_delay_test.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Preempt / IRQ disable delay thread to test latency tracers
 *
 * Copyright (C) 2018 Joel Fernandes (Google) <[email protected]>
 */

#include <linux/trace_clock.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/completion.h>

static ulong delay = …;
static char test_mode[12] = …;
static uint burst_size = …;
static int  cpu_affinity = …;

module_param_named(delay, delay, ulong, 0444);
module_param_string(…);
module_param_named(burst_size, burst_size, uint, 0444);
module_param_named(cpu_affinity, cpu_affinity, int, 0444);
MODULE_PARM_DESC(…) …;
MODULE_PARM_DESC(…) …;
MODULE_PARM_DESC(…) …;
MODULE_PARM_DESC(…) …;

static struct completion done;

static void busy_wait(ulong time)
{ … }

static __always_inline void irqoff_test(void)
{ … }

static __always_inline void preemptoff_test(void)
{ … }

static void execute_preemptirqtest(int idx)
{ … }

#define DECLARE_TESTFN(POSTFIX) …						\

/*
 * We create 10 different functions, so that we can get 10 different
 * backtraces.
 */
DECLARE_TESTFN(0)
DECLARE_TESTFN(1)
DECLARE_TESTFN(2)
DECLARE_TESTFN(3)
DECLARE_TESTFN(4)
DECLARE_TESTFN(5)
DECLARE_TESTFN(6)
DECLARE_TESTFN(7)
DECLARE_TESTFN(8)
DECLARE_TESTFN(9)

static void (*testfuncs[])(int)  = …;

#define NR_TEST_FUNCS …

static int preemptirq_delay_run(void *data)
{ … }

static int preemptirq_run_test(void)
{ … }


static ssize_t trigger_store(struct kobject *kobj, struct kobj_attribute *attr,
			 const char *buf, size_t count)
{ … }

static struct kobj_attribute trigger_attribute = …;

static struct attribute *attrs[] = …;

static struct attribute_group attr_group = …;

static struct kobject *preemptirq_delay_kobj;

static int __init preemptirq_delay_init(void)
{ … }

static void __exit preemptirq_delay_exit(void)
{ … }

module_init(preemptirq_delay_init)
module_exit(preemptirq_delay_exit)
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;