做网站多少钱一个,鲜花网站模板下载,微信小程序营销推广,培训机构连锁加盟5.1原因
线程延时是浪费CPU资源#xff0c;受否可以考虑延时的时候放弃CPU使用权#xff0c;这样就充分利用了CPU的资源。
如果线程进入阻塞状态#xff0c;没有其他线程运行#xff0c;是否可以运行一个空闲线程来做一些内存的清理等系统工作呢#xff1a;5.2 实现
5.2…5.1原因
线程延时是浪费CPU资源受否可以考虑延时的时候放弃CPU使用权这样就充分利用了CPU的资源。
如果线程进入阻塞状态没有其他线程运行是否可以运行一个空闲线程来做一些内存的清理等系统工作呢5.2 实现
5.2.1 定义空闲线程的栈
src中定义idle.c
#include rtthread.h
#include rthw.hextern rt_list_t rt_thread_priority_table[RT_THREAD_PRIORITY_MAX];#define IDLE_THREAD_STACK_SIZE 512ALIGN(RT_ALIGN_SIZE)
static rt_uint8_t rt_thread_stack[IDLE_THREAD_STACK_SIZE];5.2.2 定义空闲线程的线程控制块
struct rt_thread idle;5.2.3 定义空闲线程函数 rt_ubase_t rt_idletask_ctr 0;
void rt_thread_idle_entry(void *parameter)
{parameter parameter;while(1){rt_idletask_ctr;}
}5.2.4 空闲线程初始化
oid rt_thread_idle_init(void)
{rt_thread_init(idle,idle,rt_thread_idle_entry,RT_NULL,rt_thread_stack[0],sizeof(rt_thread_stack),RT_THREAD_PRIORITY_MAX - 1);rt_list_insert_before((rt_thread_priority_table[RT_THREAD_PRIORITY_MAX-1]),(idle.tlist));}5.3 实现阻塞延时
5.3.1 thread.c中
void rt_thread_delay(rt_tick_t tick)
{struct rt_thread *thread;thread rt_current_thread;thread-remaining_tick tick;rt_schedule();
}5.3.2 struct thread中
添加 rt_ubase_t remaining_tick;成员5.3.3 schedule.c
/* 系统调度 */
void rt_schedule(void)
{struct rt_thread *to_thread;struct rt_thread *from_thread;if(rt_current_thread idle){if(rt_flag1_thread.remaining_tick 0){from_thread rt_current_thread;to_thread rt_flag1_thread;rt_current_thread to_thread;}else if(rt_flag2_thread.remaining_tick 0){from_thread rt_current_thread;to_thread rt_flag2_thread;rt_current_thread to_thread;}else{return ;}}else{if(rt_current_thread rt_flag1_thread){if(rt_flag2_thread.remaining_tick 0){from_thread rt_current_thread;to_thread rt_flag2_thread;rt_current_thread to_thread;}else if(rt_current_thread-remaining_tick 0){from_thread rt_current_thread;to_thread idle;rt_current_thread to_thread;}else{return;}}else if(rt_current_thread rt_flag2_thread){if(rt_flag1_thread.remaining_tick 0){from_thread rt_current_thread;to_thread rt_flag1_thread;rt_current_thread to_thread;}else if(rt_current_thread-remaining_tick 0){from_thread rt_current_thread;to_thread idle;rt_current_thread to_thread;}else{return;}}}rt_hw_context_switch((rt_uint32_t)from_thread-sp,(rt_uint32_t)to_thread-sp);/* 产生上下文切换 */}
5.3.4 main.c中添加systick
void __attribute__((interrupt)) _SysTick_exception (void)
{rt_interrupt_enter();rt_tick_increase();rt_interrupt_leave();
}void SysTick_Config(uint32_t Reload)
{SYSTICK_Cmd (FALSE);SYSTICK_Reload_Config(Reload);SYSTICK_Counter_Updata(); //向ST_CV寄存器写任意值以清零当前值寄存器SYSTICK_Clock_Config(SYSTICK_SYS_CLOCK_DIV_1); //系统节拍定时器时钟源选择SCLK作为时钟源SYSTICK_Systick_INT_Enable(TRUE);SYSTICK_Cmd(TRUE);INT_Interrupt_Enable(INT_SysTick,TRUE); //使能SYSTICK中断INT_All_Enable (TRUE);
}5.3.5 系统时基更新函数
clock.c
#include rtthread.h
#include rthw.h
#include debug.hstatic rt_tick_t rt_tick 0;
extern rt_list_t rt_thread_priority_table[RT_THREAD_PRIORITY_MAX];void rt_tick_increase(void)
{rt_ubase_t i;struct rt_thread *thread;rt_tick;for(i 0;i RT_THREAD_PRIORITY_MAX;i){thread rt_list_entry(rt_thread_priority_table[i].next,struct rt_thread,tlist);if(thread-remaining_tick 0){thread-remaining_tick--;}rt_schedule();}}5.3.6 中断函数
irq.c
#include rthw.h
#include rtthread.hvolatile rt_uint8_t rt_interrupt_nest;
void rt_interrupt_enter(void)
{rt_base_t level;// RT_DEBUG_LOG(RT_DEBUG_IRQ, (irq coming..., irq nest:%d\n,// rt_interrupt_nest));level rt_hw_interrupt_disable();rt_interrupt_nest ;//RT_OBJECT_HOOK_CALL(rt_interrupt_enter_hook,());rt_hw_interrupt_enable(level);
}/*** This function will be invoked by BSP, when leave interrupt service routine** note please dont invoke this routine in application** see rt_interrupt_enter*/
void rt_interrupt_leave(void)
{rt_base_t level;// RT_DEBUG_LOG(RT_DEBUG_IRQ, (irq leave, irq nest:%d\n,// rt_interrupt_nest));level rt_hw_interrupt_disable();rt_interrupt_nest --;// RT_OBJECT_HOOK_CALL(rt_interrupt_leave_hook,());rt_hw_interrupt_enable(level);
}5.4 案例
main.c
rt_hw_interrupt_disable();
SysTick_Config(SystemCoreClock/RT_TICK_PER_SECOND);
void flag1_thread_entry( void *p_arg )
{for( ;; ){P_DBG(flag1 thread\n);flag2 1;P_DBG(flag1 thread will dela1\n);rt_thread_delay(10);flag2 0;P_DBG(flag1 thread will dela2\n);rt_thread_delay(10);}
}/* 线程2 */
void flag2_thread_entry( void *p_arg )
{for( ;; ){P_DBG(flag2 thread\n);flag2 1;rt_thread_delay(2);flag2 0;P_DBG(flag2 thread will dela1\n);rt_thread_delay(2);}
}
