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/*
* ubench.c
*
* The sole purpose of this module is to help with debugging of system
* debug tools.
*
* Copyright (C) 2015 Linaro Limited
* Daniel Thompson <daniel.thompson@linaro.org>
*/
#define pr_fmt(fmt) "ubench[%u]: " fmt, smp_processor_id()
#include <linux/smp.h>
#include <linux/debugfs.h>
#include <linux/debug_locks.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/irq_work.h>
static int ubench_do_action_on_cpu(int cpu, long (*action)(void *))
{
if (cpu == -1)
(void) action(NULL);
if (cpu < 0 || cpu > num_possible_cpus())
return -EINVAL;
pr_info("About to run %pf on cpu %d\n", action, cpu);
/* work_on_cpu() ends up performing an uninterruptible
* wait-for-completion. This means we'll lose the prompt
* whilst things run regardless of the CPU we send the
* work to.
*/
work_on_cpu(cpu, action, NULL);
return 0;
}
#define DEFINE_UBENCH_ATTRIBUTE(__fops, __action) \
static int __fops##_get(void *data, u64 *val) \
{ \
*val = __action(NULL); \
return 0; \
} \
static int __fops##_set(void *data, u64 val) \
{ \
ubench_do_action_on_cpu(val, __action); \
return 0; \
} \
DEFINE_SIMPLE_ATTRIBUTE(__fops, __fops##_get, __fops##_set, "%llu\n")
static long do_ubench_local_irq_disable(void *info)
{
int i;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
local_irq_disable();
local_irq_enable();
}
pr_info("local_irq_disable %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_local_irq_disable_fops,
do_ubench_local_irq_disable);
static long do_ubench_local_irq_save(void *info)
{
int i;
unsigned long flags;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
local_irq_save(flags);
local_irq_restore(flags);
}
pr_info("local_irq_save %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_local_irq_save_fops, do_ubench_local_irq_save);
static DEFINE_SPINLOCK(ubench_lock);
static long do_ubench_spin_lock_irq(void *info)
{
int i;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
spin_lock_irq(&ubench_lock);
spin_unlock_irq(&ubench_lock);
}
pr_info("spin_lock_irq %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_spin_lock_irq_fops, do_ubench_spin_lock_irq);
static long do_ubench_spin_lock_irqsave(void *info)
{
int i;
unsigned long flags;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
spin_lock_irqsave(&ubench_lock, flags);
spin_unlock_irqrestore(&ubench_lock, flags);
}
pr_info("spin_lock_irqsave %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_spin_lock_irqsave_fops,
do_ubench_spin_lock_irqsave);
static DEFINE_RWLOCK(ubench_rwlock);
static long do_ubench_read_lock_irq(void *info)
{
int i;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
read_lock_irq(&ubench_rwlock);
read_unlock_irq(&ubench_rwlock);
}
pr_info("read_lock_irq %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_read_lock_irq_fops, do_ubench_read_lock_irq);
static long do_ubench_read_lock_irqsave(void *info)
{
int i;
unsigned long flags;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
read_lock_irqsave(&ubench_rwlock, flags);
read_unlock_irqrestore(&ubench_rwlock, flags);
}
pr_info("read_lock_irqsave %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_read_lock_irqsave_fops,
do_ubench_read_lock_irqsave);
static long do_ubench_write_lock_irq(void *info)
{
int i;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
write_lock_irq(&ubench_rwlock);
write_unlock_irq(&ubench_rwlock);
}
pr_info("write_lock_irq %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_write_lock_irq_fops, do_ubench_write_lock_irq);
static long do_ubench_write_lock_irqsave(void *info)
{
int i;
unsigned long flags;
unsigned long long t = sched_clock();
for (i = 0; i < 1000000; i++) {
write_lock_irqsave(&ubench_rwlock, flags);
write_unlock_irqrestore(&ubench_rwlock, flags);
}
pr_info("write_lock_irqsave %llu\n", sched_clock() - t);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_write_lock_irqsave_fops,
do_ubench_write_lock_irqsave);
static long do_ubench_all(void *info)
{
do_ubench_local_irq_disable(NULL);
do_ubench_local_irq_save(NULL);
do_ubench_spin_lock_irq(NULL);
do_ubench_spin_lock_irqsave(NULL);
do_ubench_read_lock_irq(NULL);
do_ubench_read_lock_irqsave(NULL);
do_ubench_write_lock_irq(NULL);
do_ubench_write_lock_irqsave(NULL);
return 0;
}
DEFINE_UBENCH_ATTRIBUTE(ubench_all_fops, do_ubench_all);
#define E(x) { #x, &ubench_##x##_fops }
const struct
{
const char *name;
const struct file_operations *fops;
} ubench_fops_table[] = {
E(local_irq_disable),
E(local_irq_save),
E(spin_lock_irq),
E(spin_lock_irqsave),
E(read_lock_irq),
E(read_lock_irqsave),
E(write_lock_irq),
E(write_lock_irqsave),
E(all),
};
#undef E
static int __init ubench_init(void)
{
struct dentry *dir;
unsigned int i;
dir = debugfs_create_dir("ubench", NULL);
if (dir)
for (i = 0; i < ARRAY_SIZE(ubench_fops_table); i++)
(void)debugfs_create_file(ubench_fops_table[i].name,
S_IRUGO | S_IWUSR, dir, NULL,
ubench_fops_table[i].fops);
return 0;
}
module_init(ubench_init);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Thompson");
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