Subj : Help: pthread priority in Linux 2.4 Kernel
To   : comp.programming.threads
From : forSale
Date : Tue Aug 02 2005 12:08 pm

Hi,
I am running redHat 9 with all the starndard kernel config that comes with
redHat 9. I am trying to create threads with multiple priorities. However
although it looks very simple, I dont see the priority of the thread not
taking any affect. I am compling the code under "root". I think there is
something missing in the kernel config or gcc flag which affects my priority
of the thread. Following is my code

#include <pthread.h>
#include <stdio.h>
void * testThread(void *arg)
{
    while (1)) printf ("Thread--- %s \n", (unsigned char *) arg);
}
int main ()
{
 pthread_attr_t attr;
pthread_t thread1, thread2;
 struct ched_param param;
 pthread_attr_init(&attr);
param.sched_priority =20;
pthread_attr_setschedpolicy(&attr, SCHED_FIFO);
pthread_attr_setchedparam(&attr, &param)
pthread_create(&thread1, &attr,testThread, "Thread1");
param.sched_priority =22;
pthread_create(&thread2,&attr,testThread, "Thread2");
pthread_join ( thread1, NULL)
}

To compile the code I do the following

linux2.4.22> gcc testThead.c -o testThread -lpthread
linux2.4.22> ./testThead
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 2
Thread ---Thread 2
Thread ---Thread 2
Thread ---Thread 2
Thread ---Thread 2
Thread ---Thread 2
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 1
Thread ---Thread 1
......
Now Since thread 2 has higher priority than thread1. Thread1 should never
get executed once thread2 start to run.  Why is the thread1 getting
executing again.

Can someone help.. What am I doing wrong ?????
                 Thanks in advance
                          Ottawa

.