linux 线程属性参数分析(优先级，调度策略，栈大小以及其他)

1首先我们通过几个函数来了解pthread_attribute吧

/********
属性结构体：
struct attribute
{
	int detachstate;
	int schepolicy;
	struct sched_param schedparam; //调度策略优先级
	int inheritsched;
	int scope;
	size_t guardsize; //线程栈末尾的警戒区缓冲大小
	void* stackaddr; //线程站地址
	size_t stacksize; //栈大小
}pthread_attr_t


线程属性：优先级，栈大小，继承主线程与否，调度策略，系统绑定
绑定属性：一个用户线程对应一个内核线程，非绑定是由系统分配的，不确定
分离属性：线程以什么方式结束自己
不确定参数直接man -a 函数名
********/
#include
#include
#include
#include
#include
#include

void* thread_fun(void* argc)
{
	printf("file=%s,fun=%s,line=%d\n",__FILE__,__FUNCTION__,__LINE__);
}

int main()
{
	pthread_t thd,thd2;
	struct sched_param schedparam;
	int policy, priority, inherit, scope, detachstate,ret;
	size_t stacksize;
	pthread_attr_t p_attr,p_attr1;
	pthread_attr_init(&p_attr);//默认属性
	pthread_attr_init(&p_attr1);
	char tempbuf[20];
	memset(tempbuf,0,20);
	
	/**********************************获取默认线程属性********************************************/
	printf("*********************************** gain thread atribute first!*********************\n");
	pthread_attr_getschedpolicy(&p_attr,&policy); //调度策略
	if(policy == SCHED_RR)
	{
		strcpy(tempbuf,"SCHED_RR");
	}
	if(policy == SCHED_FIFO)
	{
		strcpy(tempbuf,"SCHED_FIFO");
	}
	if(policy == SCHED_OTHER)
	{
		strcpy(tempbuf,"SCHED_OTHER");
	}
	
	printf("line = %d,tempbuf= %s\n",__LINE__,tempbuf);
	
	priority = sched_get_priority_min(policy); //优先级最小值
	printf("line = %d,priority= %d\n",__LINE__,priority);
	priority =  sched_get_priority_max(policy); //优先级最大值
	printf("line = %d,priority= %d\n",__LINE__,priority);
	
	//继承主线程
	pthread_attr_getinheritsched(&p_attr,&inherit);
	if(inherit == PTHREAD_INHERIT_SCHED) 
	{
		printf("PTHREAD_INHERIT_SCHED:%d\n",inherit);
	}
	
	if(inherit == PTHREAD_EXPLICIT_SCHED) //不继承
	{
		printf("PTHREAD_EXPLICIT_SCHED:%d\n",inherit);
	}
	
	//绑定属性
	pthread_attr_getscope(&p_attr,&scope);
	if(scope == PTHREAD_SCOPE_SYSTEM) //绑定
	{
		printf("PTHREAD_SCOPE_SYSTEM:%d\n",scope);
	}
	
	if(scope = PTHREAD_SCOPE_PROCESS)//不绑定
	{
		printf("PTHREAD_SCOPE_PTHREAD:%d\n",scope);	
	}
	
	 //分离属性
	pthread_attr_getdetachstate(&p_attr,&detachstate);
	if(detachstate == PTHREAD_CREATE_DETACHED) //分离
	{
		printf("PTHREAD_CREATE_DETACHED:%d\n",detachstate);	
	}
	
	if(detachstate == PTHREAD_CREATE_JOINABLE) //不分离
	{
		printf("PTHREAD_CREATE_JOINABLE:%d\n",detachstate);
	}
	
	//获取栈大小
	pthread_attr_getstacksize(&p_attr,&stacksize);
	printf("line = %d,stacksize=%ld\n",__LINE__,stacksize);
	
	//优先级
	pthread_attr_getschedparam(&p_attr,&schedparam);
	printf("schedparam.sched_priority = %d\n",schedparam.sched_priority );
	
	ret = pthread_create(&thd,&p_attr,thread_fun,NULL);
	if(ret < 0)
	{
		printf("file=%s,fun=%s,line=%d return error\n",__FILE__,__FUNCTION__,__LINE__);
	}
	
	/*******************************设置线程属性***********************************************/
	printf("*********************************** set thread atribute second!*********************\n");
	//设置线程属性：
	policy = SCHED_FIFO;
	pthread_attr_setschedpolicy(&p_attr1,policy);
	
	//获取FIFO优先级范围
	priority = sched_get_priority_min(policy); //优先级最小值
	printf("line = %d,priority= %d\n",__LINE__,priority);
	priority =  sched_get_priority_max(policy); //优先级最大值
	
	//继承主线程
	inherit = PTHREAD_INHERIT_SCHED;
	pthread_attr_setinheritsched(&p_attr1,inherit);
	
	//绑定属性
	scope = PTHREAD_SCOPE_SYSTEM;
	pthread_attr_setscope(&p_attr1,scope);
	
	//分离属性
	detachstate = PTHREAD_CREATE_DETACHED;
	pthread_attr_setdetachstate(&p_attr1,detachstate);
	
	//优先级
	schedparam.sched_priority = 28;
	pthread_attr_setschedparam(&p_attr1,&schedparam);
	
	ret = pthread_create(&thd2,&p_attr1,thread_fun,NULL);
	if(ret < 0)
	{
		printf("file=%s,fun=%s,line=%d return error\n",__FILE__,__FUNCTION__,__LINE__);
	}
	
	/********************************获取设置之后线程属性**********************************************/
	printf("*********************************** gain thread atribute second(change)!*********************\n");
	pthread_attr_getschedpolicy(&p_attr1,&policy); //调度策略
	if(policy == SCHED_RR)
	{
		strcpy(tempbuf,"SCHED_RR");
	}
	if(policy == SCHED_FIFO)
	{
		strcpy(tempbuf,"SCHED_FIFO");
	}
	if(policy == SCHED_OTHER)
	{
		strcpy(tempbuf,"SCHED_OTHER");
	}
	
	printf("line = %d,tempbuf= %s\n",__LINE__,tempbuf);
	
	priority = sched_get_priority_min(policy); //优先级最小值
	printf("line = %d,priority= %d\n",__LINE__,priority);
	priority =  sched_get_priority_max(policy); //优先级最大值
	printf("line = %d,priority= %d\n",__LINE__,priority);
	
	pthread_attr_getinheritsched(&p_attr1,&inherit);
	if(inherit == PTHREAD_INHERIT_SCHED) //继承主线程
	{
		printf("PTHREAD_INHERIT_SCHED:%d\n",inherit);
	}
	
	if(inherit == PTHREAD_EXPLICIT_SCHED) //不继承
	{
		printf("PTHREAD_EXPLICIT_SCHED:%d\n",inherit);
	}
	
	pthread_attr_getscope(&p_attr1,&scope);//绑定属性
	if(scope == PTHREAD_SCOPE_SYSTEM) //绑定
	{
		printf("PTHREAD_SCOPE_SYSTEM:%d\n",scope);
	}
	
	if(scope = PTHREAD_SCOPE_PROCESS)//不绑定
	{
		printf("PTHREAD_SCOPE_PTHREAD:%d\n",scope);	
	}
	
	pthread_attr_getdetachstate(&p_attr1,&detachstate); //分离属性
	if(detachstate == PTHREAD_CREATE_DETACHED) //分离
	{
		printf("PTHREAD_CREATE_DETACHED:%d\n",detachstate);	
	}
	
	if(detachstate == PTHREAD_CREATE_JOINABLE) //不分离
	{
		printf("PTHREAD_CREATE_JOINABLE:%d\n",detachstate);
	}
	
	//获取栈大小
	pthread_attr_getstacksize(&p_attr1,&stacksize);
	printf("line = %d,stacksize=%ld\n",__LINE__,stacksize);
	
	//优先级
	pthread_attr_getschedparam(&p_attr1,&schedparam);
	printf("schedparam.sched_priority = %d\n",schedparam.sched_priority );
	pthread_attr_destroy(&p_attr);
	pthread_attr_destroy(&p_attr1);
	pthread_join(thd,NULL);
	pthread_join(thd2,NULL);
	
	return 0;
	
}

然后我们实现以下自己封装一个自己设置优先级，调度策略的线程吧

#include
#include
#include
#include

//#define STACK_SIZE (81920)

int STACK_SIZE = 81920;

typedef void* (*thread_fun)(void*);

//优先级定义
typedef enum sched
{
	SCHEID_FIFO = 0,
	SCHEID_RR,
	SCHEID_OTHER //分时调度
}SCHED_PRIOTY;

创建我的线程
int ros_pthread_create(pthread_t* pid,int schem_method,int privaty,int stacksize,thread_fun threadfun,void* argc)
{
	pthread_attr_t attr;
	struct sched_param schedparam;
	int priority;
	int ret = 0;
	
	memset(&attr,0,sizeof(pthread_attr_t));
	
	//pthread_attr_init(&attr);
	
	//设置线程属性：FIFO RR OTHER
	ret = pthread_attr_setschedpolicy(&attr,schem_method);
	
	//获取FIFO优先级范围
	priority = sched_get_priority_min(schem_method); //优先级最小值
	printf("line = %d,priority= %d\n",__LINE__,priority);
	priority =  sched_get_priority_max(schem_method); //优先级最大值
	printf("line = %d,priority= %d\n",__LINE__,priority);
	
	//优先级
	schedparam.sched_priority = privaty;
	ret = pthread_attr_setschedparam(&attr,&schedparam);
	
	//栈大小
	ret = pthread_attr_setstacksize(&attr,stacksize);
	
	if (ret < 0)
	{
		printf(" fun = %s line = %d return error\n",__FUNCTION__,__LINE__);
		return -1;
	}
	
	//创建线程
	ret = pthread_create(pid,&attr,threadfun,argc);
	if(ret < 0)
	{
		printf(" fun = %s line = %d return error\n",__FUNCTION__,__LINE__);
		return -1;		
	}
	
	printf(" fun = %s create success\n",__FUNCTION__);
}

void* my_fun1(void* a)
{
	while(1)
	{
		printf(" fun1 = %s line = %d return\n",__FUNCTION__,__LINE__);
	}
}

void* my_fun2(void* a)
{
	while(1)
	{
		printf(" fun2 = %s line = %d return\n",__FUNCTION__,__LINE__);
	}
}


int main()
{
	pthread_t pid1,pid2;
	int ret = ros_pthread_create(&pid1,(int)SCHEID_FIFO,1,STACK_SIZE,my_fun1,NULL);
	if(ret < 0)
	{
		printf(" fun = %s line = %d return error\n",__FUNCTION__,__LINE__);
		return -1;
	}
	
	 ret = ros_pthread_create(&pid2,(int)SCHEID_FIFO,99,STACK_SIZE,my_fun2,NULL); //数字越小，优先级越高
	if(ret < 0)
	{
		printf(" fun = %s line = %d return error\n",__FUNCTION__,__LINE__);
		return -1;
	}
	
	pthread_join(pid1,NULL);
	pthread_join(pid1,NULL);
}