process.memoryUsage()

{
  rss: 4935680,
  heapTotal: 1826816,
  heapUsed: 650472,
  external: 49879,
  arrayBuffers: 9386
}

• heapTotal 和 heapUsed指向V8’s 内存使用
• external 指向 C++ 对象的内存使用， C++对象绑定js对象，并且由V8管理
• rss, 实际占用内存，包括C++, js对象和代码三块的总计。使用 ps aux命令输出时，rss的值对应了RSS列的数值
• node js 所有buffer占用的内存

• heapTotal and heapUsed refer to V8’s memory usage.
• external refers to the memory usage of C++ objects bound to JavaScript objects managed by V8.
• rss, Resident Set Size, is the amount of space occupied in the main memory device (that is a subset of the total allocated memory) for the process, including all C++ and JavaScript objects and code.
• arrayBuffers refers to memory allocated for ArrayBuffers and SharedArrayBuffers, including all Node.js Buffers. This is also included in the external value. When Node.js is used as an embedded library, this value may be 0 because allocations for ArrayBuffers may not be tracked in that case.

process.resourceUsage()

• userCPUTime maps to ru_utime computed in microseconds. It is the same value as process.cpuUsage().user.
• systemCPUTime maps to ru_stime computed in microseconds. It is the same value as process.cpuUsage().system.
• maxRSS maps to ru_maxrss which is the maximum resident set size used in kilobytes.
• sharedMemorySize maps to ru_ixrss but is not supported by any platform.
• unsharedDataSize maps to ru_idrss but is not supported by any platform.
• unsharedStackSize maps to ru_isrss but is not supported by any platform.
• minorPageFault maps to ru_minflt which is the number of minor page faults for the process, see this article for more details.
• majorPageFault maps to ru_majflt which is the number of major page faults for the process, see this article for more details. This field is not supported on Windows.
• swappedOut maps to ru_nswap but is not supported by any platform.
• fsRead maps to ru_inblock which is the number of times the file system had to perform input.
• fsWrite maps to ru_oublock which is the number of times the file system had to perform output.
• ipcSent maps to ru_msgsnd but is not supported by any platform.
• ipcReceived maps to ru_msgrcv but is not supported by any platform.
• signalsCount maps to ru_nsignals but is not supported by any platform.
• voluntaryContextSwitches maps to ru_nvcsw which is the number of times a CPU context switch resulted due to a process voluntarily giving up the processor before its time slice was completed (usually to await availability of a resource). This field is not supported on Windows.
• involuntaryContextSwitches maps to ru_nivcsw which is the number of times a CPU context switch resulted due to a higher priority process becoming runnable or because the current process exceeded its time slice. This field is not supported on Windows.

console.log(process.resourceUsage());
/*
  Will output:
  {
    userCPUTime: 82872,
    systemCPUTime: 4143,
    maxRSS: 33164,
    sharedMemorySize: 0,
    unsharedDataSize: 0,
    unsharedStackSize: 0,
    minorPageFault: 2469,
    majorPageFault: 0,
    swappedOut: 0,
    fsRead: 0,
    fsWrite: 8,
    ipcSent: 0,
    ipcReceived: 0,
    signalsCount: 0,
    voluntaryContextSwitches: 79,
    involuntaryContextSwitches: 1
  }
*/