求助Linux Hrtimer高精度定时器问题
- C/C++ code
#include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/netdevice.h> #include <linux/pci.h> #include <linux/device.h> #include <linux/time.h> #include <linux/skbuff.h> #include <linux/jiffies.h> #include <linux/interrupt.h> #include <linux/hrtimer.h> #include <linux/ktime.h> #include <asm/irq.h> MODULE_DESCRIPTION("Just for hrtimer test"); MODULE_AUTHOR("summon (*********@163.com)"); MODULE_LICENSE("GPL"); #define DyS_HRTIMER_US_TO_NS(x) (x)*1000 static struct hrtimer hrtimer_for_test; unsigned long g_hr_times = 0; enum hrtimer_restart hrtimer_callback_func(struct hrtimer *p_timer) { g_hr_times++; if (net_ratelimit()) { printk(KERN_DEBUG "The function hrtimer_callback_func, times is %d\n", g_hr_times); } return HRTIMER_RESTART; } static int hrtimer_init_module(void) { printk( KERN_DEBUG "Module hrtimer_init_module init\n" ); ktime_t ktime; unsigned long delay_in_ns = DyS_HRTIMER_US_TO_NS(250); ktime = ktime_set(1,delay_in_ns); hrtimer_init(&hrtimer_for_test,CLOCK_MONOTONIC,HRTIMER_MODE_REL); hrtimer_for_test.function = hrtimer_callback_func; hrtimer_start(&hrtimer_for_test,ktime,HRTIMER_MODE_REL); return 0; } static void hrtimer_exit_module(void) { printk( KERN_DEBUG "Module hrtimer_exit_module exit\n" ); } module_init(hrtimer_init_module); module_exit(hrtimer_exit_module);
一个测试程序,最后结果是每秒钟打印1千万次左右,总之不是我想要的1+250us的。
哪位用过的同学告诉一声,万分感谢哈,google过了,不好使
enum hrtimer_restart hrtimer_callback_func(struct hrtimer *p_timer)
{
g_hr_times++;
if (net_ratelimit())
{
printk(KERN_DEBUG "The function hrtimer_callback_func, times is %d\n", g_hr_times);
}
hrtimer_for_test.expires=ktime_add_ns(hrtimer_for_test.expires,(u64)(1*1E9+250*1000);
return HRTIMER_RESTART;
}
在定时器重启前楼主没有更新定时器,所以直接返回HRTIMER_RESTART的后果就是又立即直接调用hrtimer_callback_func函数