请问调用rt_thread_create（）创建线程，初始化定时器有何用处

choose521

调用rt_thread_create（）创建线程的时候，调用了下面的代码，作用是什么？

/* initialize thread timer */
rt_timer_init(&(thread->thread_timer),thread->name,rt_thread_timeout,thread,0,RT_TIMER_FLAG_ONE_SHOT);
为什么要创建这个定时器？

在系统时钟中断回调函数里面，已经调用了下面的代码
( g( ^' w& G! o+ W/ }9 a
) H8 s2 J! E$ m8 M/ |: Q& Y, f0 `void rt_tick_increase(void)
& T' T/ Q4 S% e# ]{
0 w$ Y% y4 t- ^, K% S3 Sstruct rt_thread thread;
; X$ |! _$ w9 y# d4 f: Y/ increase the global tick /
. K0 l- w$ D: K, L++ rt_tick;
/ check time slice /
thread = rt_thread_self();
: F6 a. g7 d2 o+ s-- thread->remaining_tick;
6 r. t4 Q; B0 @! r3 q) Zif (thread->remaining_tick == 0)
{
/ change to initialized tick /
& h" |( R7 w( `) e1 hthread->remaining_tick = thread->init_tick;
/ yield /
rt_thread_yield();
" `7 h- V  e+ _  J0 n) n; V}
' O# P" B4 V0 u6 I& h* ~/ check timer */
9 S2 B5 y$ I& ?; ort_timer_check();
1 J. p3 Z) R8 Q$ \}
上面的代码已经会去判断remaining_tick，这个为0就执行让出cpu操作了。

opipo

用来控制挂起时间的。例如你主动调用delay或者阻塞于获取信号量等都会用到这个定时器。截取了一段信号量获取函数中的源码：
`
/ start /
- a7 _6 \0 e9 f5 x) nrt_ipc_list_suspend(&(sem->parent.suspend_thread),
thread,
6 ?: C9 h; n/ _9 u: zsem->parent.parent.flag);
! g. H0 o9 U5 ^2 n* t
& @* V2 t0 O" s7 @: P/* has waiting time, start thread timer */
if (time > 0)
{
RT_DEBUG_LOG(RT_DEBUG_IPC, ("set thread:%s to timer list\n",
thread->name));
8 C6 x  {: {( M# |& U/* reset the timeout of thread timer and start it */
/ ?/ V! T4 m/ Nrt_timer_control(&(thread->thread_timer),
RT_TIMER_CTRL_SET_TIME,
' f' U3 V7 n! U& B&time);
rt_timer_start(&(thread->thread_timer));
}
/* enable interrupt */
# j' ?" w, [/ w9 R& u, \rt_hw_interrupt_enable(temp);
/* do schedule */
rt_schedule(); rt_ipc_list_suspend(&(sem->parent.suspend_thread),
# b5 Y% I; g4 Z4 d- S* M6 k/ ^thread,
5 ], z9 w  X5 c, Vsem->parent.parent.flag);
/* has waiting time, start thread timer */
9 e# Y) G) N! h' mif (time > 0)
" b6 _4 E6 I( J. m9 n{
RT_DEBUG_LOG(RT_DEBUG_IPC, ("set thread:%s to timer list\n",
thread->name));
6 [" a: @. ?! M1 E3 h/* reset the timeout of thread timer and start it */
1 }6 G* X. L" b/ D! Trt_timer_control(&(thread->thread_timer),
) B4 y5 g* j, n* ~  W: o6 DRT_TIMER_CTRL_SET_TIME,
0 E6 [; V; l6 {8 b&time);
, e6 r* |( |5 N6 @) Brt_timer_start(&(thread->thread_timer));
4 R; {! F2 j- W( q}
/* enable interrupt */
rt_hw_interrupt_enable(temp);
6 [4 b! b5 N$ s, u  C/* do schedule */
" x. x4 T; v% r& D. F( yrt_schedule();`

Blah

楼上说的很不错的

land

可以试试一楼的方法