我正在尝试使用 PAPI 读取硬件性能计数器，并编写了以下代码：
#include <stdio.h>
#include <stdlib.h>
#include "papi.h" /* This needs to be included every time you use PAPI */
#include <unistd.h>
#define NUM_EVENTS 2
#define ERROR_RETURN(retval) { fprintf(stderr, "Error %d %s:line %d: \n", retval,__FILE__,__LINE__); exit(retval); }
int main(int argc, char *argv[])
{
if(argc<=1) {
printf("Pid is not provided, I will die now :( ...");
exit(1);
} //otherwise continue on our merry way....
int EventSet = PAPI_NULL;
int tmp, i;
/*must be initialized to PAPI_NULL before calling PAPI_create_event*/
long long values[NUM_EVENTS];
/*This is where we store the values we read from the eventset */
/* We use number to keep track of the number of events in the EventSet */
int retval, number;
char errstring[PAPI_MAX_STR_LEN];
pid_t pid = atoi(argv[1]);
unsigned int l2miss = 0x0;
unsigned int data_all_from_l2 = 0x0;
/***************************************************************************
* This part initializes the library and compares the version number of the*
* header file, to the version of the library, if these don't match then it *
* is likely that PAPI won't work correctly.If there is an error, retval *
* keeps track of the version number. *
***************************************************************************/
if((retval = PAPI_library_init(PAPI_VER_CURRENT)) != PAPI_VER_CURRENT )
ERROR_RETURN(retval);
/* Creating the eventset */
if ( (retval = PAPI_create_eventset(&EventSet)) != PAPI_OK)
ERROR_RETURN(retval);
/* Add Native event to the EventSet */
// if ( (retval = PAPI_event_name_to_code("PM_DATA_FROM_L2MISS",&l2miss)) != PAPI_OK)
if ( (retval = PAPI_event_name_to_code("PM_L3_CO_MEM",&l2miss)) != PAPI_OK)
ERROR_RETURN(retval);
if ( (retval = PAPI_add_event(EventSet, l2miss)) != PAPI_OK)
ERROR_RETURN(retval);
/* Add Native event to the EventSet */
if ( (retval = PAPI_event_name_to_code("PM_DATA_ALL_FROM_L2",&data_all_from_l2)) != PAPI_OK)
ERROR_RETURN(retval);
if ( (retval = PAPI_add_event(EventSet, data_all_from_l2)) != PAPI_OK)
ERROR_RETURN(retval);
/* get the number of events in the event set */
number = 0;
if ( (retval = PAPI_list_events(EventSet, NULL, &number)) != PAPI_OK)
ERROR_RETURN(retval);
printf("There are %d events in the event set\n", number);
retval = PAPI_attach( EventSet, ( unsigned long ) pid );
if ( retval != PAPI_OK )
ERROR_RETURN(retval);
/* Start counting */
if ( (retval = PAPI_start(EventSet)) != PAPI_OK)
ERROR_RETURN(retval);
while(kill(pid,0)==0)
{
if ( (retval=PAPI_read(EventSet, values)) != PAPI_OK)
ERROR_RETURN(retval);
printf("The L2 Miss are %lld \n",values[0]);
printf("The data_all_from_l2 are %lld \n",values[1]);
sleep(1);
}//while
/* Stop counting and store the values into the array */
if ( (retval = PAPI_stop(EventSet, values)) != PAPI_OK)
ERROR_RETURN(retval);
printf("Total L2 Miss are %lld \n",values[0]);
printf("Total data_all_from_l2 are %lld \n",values[1]);
/* free the resources used by PAPI */
PAPI_shutdown();
exit(0);
}
我使用以下命令编译它：
gcc -I/apps/PAPI/5.5.0/GCC/5.4.0/CUDA/8.0/include -O0 pid_ex.c -L/apps/PAPI/5.5.0/GCC/5.4.0/CUDA/8.0/lib -lpapi -o pid_ex
我像这样运行它：
./pid_ex 7865
其中 7865 是正在运行的进程的进程 ID。
问题是它显示零值而不是显示计数器值。
谁能让我知道它为什么会这样？为什么它没有获得价值？