[request for comments ] performance issue : calloc & free vs creating subpool for cache memory management???

[Sadaf Alvi]

thanx! i wanna write a cache library and come up with 2 different techniques to allocate cache memory 1) use calloc & free for each node 2) create a subpool in pconf for each node i did some experiment with both.    #define LOOP_SIZE 10000 #define MEM_SIZE 400     long iCounter;  char *ptr = NULL;  apr_pool_t *sub_pool = NULL;  clock_t t1,t2;                    for(iCounter=0; iCounter < LOOP_SIZE; iCounter++ ) {      apr_pool_create(&sub_pool,conf->pool);      ptr = apr_pcalloc(sub_pool,MEM_SIZE);      apr_pool_destroy(sub_pool);  }  //end time: subpool    t2=clock();  ap_log_error(APLOG_MARK, APLOG_ERR, 0, 0,"SUB_POOL :  %.4lf seconds of processing\n", (t2-t1)/(double)CLOCKS_PER_SEC);      //start time: calloc  t1=clock();          for(iCounter=0; iCounter < LOOP_SIZE; iCounter++ ) {      ptr = (char *) calloc( sizeof(char),  MEM_SIZE);      if(ptr)         free((void*) ptr);  }    //end time: calloc  t2=clock();  ap_log_error(APLOG_MARK, APLOG_ERR, 0, 0,"CALLOC : %.4lf seconds of processing\n", (t2-t1)/(double)CLOCKS_PER_SEC);   tried above code with  LOOP_SIZE = 10000, MEM_SIZE = 400   found in error_log   SUB_POOL : 0.0200 seconds of processing CALLOC : 0.0200 seconds of processing                 tried above code with LOOP_SIZE = 60000, MEM_SIZE = 200   found in error_log   SUB_POOL : 0.1300 seconds of processing CALLOC : 0.0700 seconds of processing