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Set thread priority for linux [message #36495]

Sat, 02 June 2012 18:50

tojocky
Messages: 607
Registered: April 2008
Location: UK

Contributor

Hello,

Having some experience with thread priority on linux I propose to implent Thread::Priority(int);

Ok the implementation for linux is:

....
#ifdef PLATFORM_POSIX
	int policy, res;
	struct sched_param param;
	
	if ((res = pthread_getschedparam(handle, &policy, &param)) != 0){
		return;
		//TODO: should returns the error
	}
	if(percent <= 25){
		policy = SCHED_IDLE;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*percent/25;
	}else if(percent <= 75){
		policy = SCHED_BATCH;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(percent-25)/50;
	}else if(percent <= 125){
		policy = SCHED_OTHER;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(percent-75)/50;
	}else if(percent <= 175){// should be a root
		policy = SCHED_FIFO;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(percent-125)/50;
	}else{
		policy = SCHED_RR;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(minmax(percent, 175, 225)-175)/25;
	}
	
	if ((res = pthread_setschedparam(handle, policy, &param)) != 0){
		return;
		//TODO: should returns the error
	}
#endif
....

and the hole method:

void Thread::Priority(int percent)
{
	ASSERT(IsOpen());
#ifdef PLATFORM_WIN32
	int prior;
	if(percent <= 25)
		prior = THREAD_PRIORITY_LOWEST;
	else if(percent <= 75)
		prior = THREAD_PRIORITY_BELOW_NORMAL;
	else if(percent <= 125)
		prior = THREAD_PRIORITY_NORMAL;
	else if(percent <= 175)
		prior = THREAD_PRIORITY_ABOVE_NORMAL;
	else
		prior = THREAD_PRIORITY_HIGHEST;
	SetThreadPriority(handle, prior);
#endif
#ifdef PLATFORM_POSIX
	int policy, res;
	struct sched_param param;
	
	if ((res = pthread_getschedparam(handle, &policy, &param)) != 0){
		return;
		//TODO: should returns the error
	}
	if(percent <= 25){
		policy = SCHED_IDLE;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*percent/25;
	}else if(percent <= 75){
		policy = SCHED_BATCH;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(percent-25)/50;
	}else if(percent <= 125){
		policy = SCHED_OTHER;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(percent-75)/50;
	}else if(percent <= 175){// should be a root
		policy = SCHED_FIFO;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(percent-125)/50;
	}else{
		policy = SCHED_RR;
		param.sched_priority = (sched_get_priority_max(policy) - sched_get_priority_min(policy))*(minmax(percent, 175, 225)-175)/25;
	}
	
	if ((res = pthread_setschedparam(handle, policy, &param)) != 0){
		return;
		//TODO: should returns the error
	}
#endif
}

Any comments are welcome!

Best regards,
Ion.

[Updated on: Sat, 02 June 2012 18:58]

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