From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jaiprakash" <jaiprakash@inablers.net>
To: ecos-discuss@sources.redhat.com
Subject: [ECOS] Thread related queries
Date: Sat, 25 Aug 2001 04:09:00 -0000
Message-id: <200108251135.RAA16753@inablers.net>
X-SW-Source: 2001-08/msg00846.html

Hello,
I have the following queries regarding implementation of threading in 
ecos:
 
1. Does ecos consider main() as a running thread or is it just an entry 
point to the system.
2. What is Cyg_Idle_thread used for? its functionality is not clear.
3. I was trying to compare following piece of code on linux 6.2 and 
ecos running on my board.
 
 
#include <pthread.h>
#include <signal.h>
#define NUM_THREADS     3

void *PrintThreadid(void *threadid)
{
  int i;
  for(;;){
      printf("\nthread %d\n",threadid);
      i = sleep(1);  
      if(i) {
           printf("return value from sleep() %d", i);
      }
  }
}

int main()
{
    pthread_t threads[NUM_THREADS];
    int rc, t,i,j;
    int *thread_return;
    pthread_attr_t attr;
 
    rc =  pthread_attr_init(&attr);
    if(rc){
       printf("ERROR: return code from pthread_attr_init %d", rc);
    } 
    printf("\n creating threads\n");  
    for(t=0;t < NUM_THREADS;t++){
        rc = pthread_create(&threads[t], &attr, PrintThreadid, (void *)
t);
        if (rc){
             printf("ERROR; return code from pthread_create()%d ", rc);
        }
   }
    printf("\n running main thread\n");
    pthread_attr_destroy(&attr);
    for(t=0;t < NUM_THREADS;t++){
        rc = pthread_join(threads[t], (void *)&thread_return); 
        if(rc){
           printf("ERROR: return code from pthread_join %d", rc);
        }
        printf("Completed join with thread %d thread_return = %d\n",t, 
thread_return );
    }
    
    while(1) ;
}

 
 
On linux the control goes to main() once, later the threads keep 
running continuously. But in ecos the main() seems to get more 
timeslice (15 - 20 times more) than the three threads. My basic clock 
tick is 0.5 secs and timeslicing is 2 ticks. can you give me some 
inputs regarding the difference of behaviour eventhough i am using 
pthread calls. 
There is not much documentation regarding implementation of threading 
in ecos.
 
Thanking you in advance.
 
Jaiprakash N