title: Why i get nothing with PCM(Intel performance counter monitor) -- c++ API
body: <p>root@dellr740:/ycsb_build# sudo ./ycsb</p>
  <p>IBRS and IBPB supported  : yes</p>
  <p>STIBP supported          : yes</p>
  <p>Spec arch caps supported : yes</p>
  <p>Number of physical cores: 20</p>
  <p>Number of logical cores: 40</p>
  <p>Number of online logical cores: 40</p>
  <p>Threads (logical cores) per physical core: 2</p>
  <p>Num sockets: 1</p>
  <p>Physical cores per socket: 20</p>
  <p>Core PMU (perfmon) version: 4</p>
  <p>Number of core PMU generic (programmable) counters: 4</p>
  <p>Width of generic (programmable) counters: 48 bits</p>
  <p>Number of core PMU fixed counters: 3</p>
  <p>Width of fixed counters: 48 bits</p>
  <p>Nominal core frequency: 2100000000 Hz</p>
  <p>IBRS enabled in the kernel   : yes</p>
  <p>STIBP enabled in the kernel  : no</p>
  <p>The processor is not susceptible to Rogue Data Cache Load: yes</p>
  <p>The processor supports enhanced IBRS                     : yes</p>
  <p>Package thermal spec power: 125 Watt; Package minimum power: 63 Watt; Package maximum power: 307 Watt;</p>
  <p>ERROR: Secure Boot detected. Recompile PCM with -DPCM_USE_PERF or disable Secure Boot.
  Socket 0: 2 memory controllers detected with total number of 6 channels. 0 QPI ports detected. 2 M2M (mesh to memory) blocks detected.</p>
  <p>.......
  .......
  ......
  <em><strong>result here, pcm metric, i get  0 byte</strong></em></p>
  <p>WARNING: Custom counter 0 is in use. MSR_PERF_GLOBAL_INUSE on core 0: 0x800000000000000f</p>
  <p>WARNING: Custom counter 1 is in use. MSR_PERF_GLOBAL_INUSE on core 0: 0x800000000000000f</p>
  <p>WARNING: Custom counter 2 is in use. MSR_PERF_GLOBAL_INUSE on core 0: 0x800000000000000f</p>
  <p>WARNING: Custom counter 3 is in use. MSR_PERF_GLOBAL_INUSE on core 0: 0x800000000000000f</p>
  <p>WARNING: Core 0 IA32_PERFEVTSEL0_ADDR are not zeroed 1245244</p>
  <p>Error opening PCM: 2</p>
  <p>Zeroed PMU registers</p>
  <p>Cleaning up</p>
  <p>Zeroed uncore PMU registers</p>
  <p>PCM Metrics:</p>
  <pre><code>L2 HitRatio: 1
  
  L3 HitRatio: -1
  
  L2 misses: 0
  
  L3 misses: 0
  
  DRAM Reads (bytes): 0
  
  DRAM Writes (bytes): 0
  
  NVM Reads (bytes): 0
  
  NVM Writes (bytes): 0
  </code></pre>