perf.c.save

// perf.c with only cpu-cycles
// 28.10.2016


///////////////////////////////// start： 头文件的选择///////////////////////////////////////////
// 看有没有VT/SCOREP，然后决定包含对应的头文件。
//in my case, 在build时写了-DSCOREP_DIR=~/install/scorep, 所以这里检测到了scorep，就包含了scorep_MetricPlugin.h
 
#ifdef SCOREP
#include <scorep/SCOREP_MetricPlugins.h>
#else
#error "You need Score-P  to compile this plugin"
#endif /* SCOREP*/
 

#include <inttypes.h>  //PRIu64
#include <stdlib.h>   // strtoll();   malloc();
#include <string.h>
#include <stdio.h>
#include <errno.h>   
#include <unistd.h>  
#include <stdint.h>
#include <sys/syscall.h>


#include <linux/perf_event.h>
////////////////////////////// end： 头文件的选择////////////////////////////////////////////


/* init and fini do not do anything */
/* This is intended! */
int32_t init(){
  return 0;
}
void fini(){
  /* we do not close perfs file descriptors */
  /* as we do not store this information */
}

/////////////////begin: assign value to all attr.type , attr.config./////////////////////////////////////////////////

/* This function writes the attr definitions for a given event name
 * If the event has not been found, attr->type is PERF_TYPE_MAX
 * */
void build_perf_attr(struct perf_event_attr * attr, char * name)
{
  
  memset( attr, 0, sizeof( struct perf_event_attr ) ); //The first n bits of attr will be replaced by n 0s. n = sizeof( struct perf_event_attr).
  attr->config1 = 0;
  attr->config2 = 0;
  attr->type    = PERF_TYPE_MAX;


  // those that will be used.
 
  if ( ( strstr( name, "cpu-cycles" ) == name ) || ( strstr( name, "cycles" ) == name ) )
  {
    attr->type   = PERF_TYPE_HARDWARE;
    attr->config = PERF_COUNT_HW_CPU_CYCLES;
  }
  if ( strstr( name, "instructions" ) == name )
  {
    attr->type   = PERF_TYPE_HARDWARE;
    attr->config = PERF_COUNT_HW_INSTRUCTIONS;
  }
  if ( strstr( name, "cache-references" ) == name )
  {
    attr->type   = PERF_TYPE_HARDWARE;
    attr->config = PERF_COUNT_HW_CACHE_REFERENCES;
  }
  if ( strstr( name, "cache-misses" ) == name )
  {
    attr->type   = PERF_TYPE_HARDWARE;
    attr->config = PERF_COUNT_HW_CACHE_MISSES;
  }
  if ( ( strstr( name, "branch-instructions" ) == name ) || ( strstr( name, "branches" ) == name ) )
  {
    attr->type   = PERF_TYPE_HARDWARE;
    attr->config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
  }
  if ( strstr( name, "branch-misses" ) == name )
  {
    attr->type   = PERF_TYPE_HARDWARE;
    attr->config = PERF_COUNT_HW_BRANCH_MISSES;
  }

}


/////////////////end: assign value to all attr.type , attr.config./////////////////////////////////////////////////

/* registers perf event */
// it provides a unique ID for each metric.
int32_t add_counter(char * event_name){
  int id = 0;

  if(strstr( event_name, "energy-cores" ) == event_name)
  {
    id = 1;
  }
  
  if (id<=0){
    fprintf(stderr, "Unable to open counter \"%s\". Aborting.\n",event_name);
    return -1;
  }

  printf("%s's id = %d\n",event_name, id);
  return id;
}

/* reads value */
uint64_t get_value(int id){
  
  int fd1;
  uint64_t count1=0;
  struct perf_event_attr attr1;
  size_t res1;

  build_perf_attr(&attr1, "instructions");
  fd1 = syscall(__NR_perf_event_open, &attr1, 0, -1, -1, 0);
  res1 =read(fd1, &count1, sizeof(uint64_t));

  if (res1!=sizeof(uint64_t))
    return !0;
 /*
  if(id == 1){
    build_perf_attr(&attr1, "instructions");
    fd1 = syscall(__NR_perf_event_open, &attr1, 0, -1, -1, 0);
    res1 =read(fd1, &count1, sizeof(uint64_t));
  }

  if (res1!=sizeof(uint64_t))
    return !0;
 */
  
   return 123;
}

#ifdef SCOREP

SCOREP_Metric_Plugin_MetricProperties * get_event_info(char * event_name)
{
  SCOREP_Metric_Plugin_MetricProperties * return_values;
  uint64_t id = add_counter(event_name);

    /* wrong metric */
  if (id == 0){
    fprintf(stderr, "PERF metric not recognized: %s", event_name );
    return NULL;
  }
  return_values= malloc(2 * sizeof(SCOREP_Metric_Plugin_MetricProperties) );   /// why 2????
  if (return_values==NULL){
        fprintf(stderr, "Score-P Perf Plugin: failed to allocate memory for passing information to Score-P.\n");
        return NULL;
  }
  return_values[0].name        = strdup(event_name);  //strdup == duplicate.
  return_values[0].unit        = NULL;
  return_values[0].description = NULL;
  return_values[0].mode        = SCOREP_METRIC_MODE_ACCUMULATED_START;
  return_values[0].value_type  = SCOREP_METRIC_VALUE_UINT64;
  return_values[0].base        = SCOREP_METRIC_BASE_DECIMAL;
  return_values[0].exponent    = 0;
  return_values[1].name=NULL;
  return return_values;
}

bool get_optional_value( int32_t id, uint64_t* value ){
  *value=get_value(id);
  return true;
}

/**
 * This function get called to give some informations about the plugin to scorep
 */

//说明了这个plugin的名字，还有内部的一些结构。
SCOREP_METRIC_PLUGIN_ENTRY( perf_plugin )
{
    /* Initialize info data (with zero) */
    SCOREP_Metric_Plugin_Info info;
    memset( &info, 0, sizeof( SCOREP_Metric_Plugin_Info ) );

    /* Set up the structure */
    info.plugin_version               = SCOREP_METRIC_PLUGIN_VERSION;
    info.run_per                      = SCOREP_METRIC_PER_THREAD;
    info.sync                         = SCOREP_METRIC_SYNC;
    info.initialize                   = init;
    info.finalize                     = fini;
    info.get_event_info               = get_event_info;
    info.add_counter                  = add_counter;
    info.get_current_value            = get_value;
    info.get_optional_value           = get_optional_value;

    return info;
}
#endif /* SCOREP */