通过python获取内存使用率

Question

我无法使用psutil检索系统的内存使用情况

当我运行代码时，它会正确检索cpu使用情况，但当它试图获取内存时，它会抛出AccessDenied错误

代码：

if(pi['name']=='java.exe'):
    pro=psutil.Process(0)
    cpu=pro.cpu_percent(1)
    memory=pro.memory_full_info().uss/(1024*1024)
    return memory,cpu

错误消息：

psutil.AccessDenied (pid=0)

如何获取内存使用率

Answer 1

psutil.Process()接受一个参数-进程标识符（PID）。如果在没有参数或使用None调用它，则使用当前进程的pid

在窗口上，pid 0是系统空闲进程的，它需要SYSTEM权限

pro=psutil.Process(0) # here's your problem

如果要获取java.exe的内存/cpu使用率，必须获取pid，然后使用psutil。在下面的示例中，我使用了firefox.exe：

import psutil
from ctypes import *
from ctypes.wintypes import *

class PROCESSENTRY32W(Structure):
    _fields_ = [("dwSize", DWORD),
                ("cntUsage", DWORD),
                ("th32ProcessID", DWORD),
                ("th32DefaultHeapID", POINTER(ULONG)),
                ("th32ModuleID", DWORD),
                ("cntThreads", DWORD),
                ("th32ParentProcessID", DWORD),
                ("pcPriClassBase", LONG),
                ("dwFlags", DWORD),
                ("szExeFile", c_wchar * MAX_PATH)]

def get_processes():
    TH32CS_SNAPPROCESS = 0x00000002
    INVALID_HANDLE_VALUE = -1

    CreateToolhelp32Snapshot = windll.kernel32.CreateToolhelp32Snapshot
    CreateToolhelp32Snapshot.argtypes = [DWORD, DWORD]
    CreateToolhelp32Snapshot.restype = HANDLE

    Process32FirstW = windll.kernel32.Process32FirstW
    Process32FirstW.argtypes = [HANDLE, POINTER(PROCESSENTRY32W)]
    Process32FirstW.restype = BOOL

    Process32NextW = windll.kernel32.Process32NextW
    Process32NextW.argtypes = [HANDLE, POINTER(PROCESSENTRY32W)]
    Process32NextW.restype = BOOL

    CloseHandle = windll.kernel32.CloseHandle
    CloseHandle.argtypes = [HANDLE]
    CloseHandle.restype = BOOL

    snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0)
    if snapshot == INVALID_HANDLE_VALUE:
        return []

    try:
        process_entry = PROCESSENTRY32W()
        process_entry.dwSize = sizeof(PROCESSENTRY32W)
        if not Process32FirstW(snapshot, byref(process_entry)):
            return []

        processes = []
        while Process32NextW(snapshot, byref(process_entry)):
            processes.append((process_entry.th32ProcessID, process_entry.szExeFile))
    finally:
        CloseHandle(snapshot)
        #print("Closed handle")

    return processes

for pid, name in get_processes():
    if name == "firefox.exe":
        pro = psutil.Process(pid)
        cpu = pro.cpu_percent(1.0)
        memory = pro.memory_full_info().uss/(1024*1024)
        print(memory, cpu)

输出：

471.2890625 1.6
127.15234375 25.0
18.50390625 0.0
668.09375 0.0
706.6875 0.0
512.671875 0.0
648.953125 4.7
1037.0859375 4.7
1160.1015625 98.4
337.46484375 0.0
1418.72265625 1.6
0.90625 0.0
0.90625 0.0