PDH获取CPU利用率统计不正确的问题

amoyppa

windows下使用PDH获取CPU的利用率，统计的数据很不正确，期待各位高手指点一二。代码如下：

1. 
   
2. #include <windows.h>
   
3. #include <tchar.h>
   
4. #include <stdio.h>
   
5. #include <pdh.h>
   
6. #include <conio.h>
   
7. #pragma comment(lib, "pdh.lib")
   
8. CONST ULONG SAMPLE_INTERVAL_MS    = 1000;
   
9. int getCpuUsage(int flag){
   
10.         HQUERY hQuery = NULL;
    
11.         CONST ULONG SAMPLE_INTERVAL_MS    = 1000;
    
12.         PDH_STATUS pdhStatus;
    
13. 
    
14.         pdhStatus = PdhOpenQuery(NULL,NULL, &hQuery);  
    
15.         if(pdhStatus != ERROR_SUCCESS) {
    
16.                 return -1;  
    
17.         }  
    
18.         HCOUNTER hCounter;  
    
19.         //if(flag)
    
20.         {
    
21. //                printf("2008 os\n");
    
22. //                pdhStatus = PdhAddCounter(hQuery,"\\Processor(*)\\% Processor Time", 0, &hCounter);  
    
23.         }
    
24. //        else
    
25.         {
    
26.                 printf(" 2003 os and 2008 \n");
    
27.                 PDH_COUNTER_PATH_ELEMENTS pcpe;  
    
28.                 TCHAR szFullPathBuffer[MAX_PATH] = TEXT("");  
    
29.                 DWORD dwSize = sizeof(szFullPathBuffer);  
    
30. 
    
31.                 pcpe.szMachineName = TEXT("127.0.0.1");  
    
32.                 pcpe.szObjectName = TEXT("Processor");  
    
33.                 pcpe.szInstanceName = TEXT("_Total");  
    
34.                 pcpe.szCounterName = TEXT("% Processor Time");  
    
35.                 pcpe.dwInstanceIndex = -1;  
    
36.                 pcpe.szParentInstance = NULL;  
    
37. 
    
38.                 pdhStatus = PdhMakeCounterPath(&pcpe, szFullPathBuffer, &dwSize, 0);  
    
39.                 if(pdhStatus != ERROR_SUCCESS) {  
    
40. 
    
41.                         goto exit_prog;  
    
42.                 }
    
43.                 pdhStatus = PdhAddCounter(hQuery, szFullPathBuffer, 0, &hCounter);
    
44.                 //pdhStatus = PdhAddCounter(hQuery,"\\Processor(_Total)\\% Processor Time", 0, &hCounter);
    
45.                 //pdhStatus = PdhAddCounter(hQuery, _TEXT ( "Processor(_Total)\\%Processor Time" ), 0, &hCounter);         
    
46.                 //pdhStatus = PdhAddCounter(hQuery,"\\SUPER\\Processor(_Total)\\% Processor Time", 1, &hCounter);
    
47.         }
    
48. 
    
49. 
    
50.         if(pdhStatus != ERROR_SUCCESS) {  
    
51. 
    
52.                 goto exit_prog;  
    
53.         }  
    
54.         pdhStatus = PdhCollectQueryData(hQuery);
    
55.         if(pdhStatus != ERROR_SUCCESS) {  
    
56. 
    
57.                 goto exit_prog;  
    
58.         }
    
59.         PDH_FMT_COUNTERVALUE pfc;  
    
60.         DWORD dwOpt;
    
61.         Sleep(SAMPLE_INTERVAL_MS);
    
62.         pdhStatus = PdhCollectQueryData(hQuery);
    
63.         Sleep(100);
    
64.         pdhStatus = PdhCollectQueryData(hQuery);
    
65.                 Sleep(100);
    
66.         pdhStatus = PdhCollectQueryData(hQuery);
    
67.                 Sleep(100);
    
68.         pdhStatus = PdhCollectQueryData(hQuery);
    
69.                 Sleep(100);
    
70.         pdhStatus = PdhCollectQueryData(hQuery);
    
71.                 Sleep(100);
    
72.         pdhStatus = PdhCollectQueryData(hQuery);
    
73.                 Sleep(100);
    
74.         pdhStatus = PdhCollectQueryData(hQuery);
    
75.                 Sleep(100);
    
76.         pdhStatus = PdhCollectQueryData(hQuery);
    
77.                 Sleep(100);
    
78.         pdhStatus = PdhCollectQueryData(hQuery);
    
79.                 Sleep(100);
    
80.         pdhStatus = PdhCollectQueryData(hQuery);
    
81.                 Sleep(100);
    
82.         pdhStatus = PdhCollectQueryData(hQuery);
    
83.                 Sleep(100);
    
84.         pdhStatus = PdhCollectQueryData(hQuery);
    
85.                 Sleep(100);
    
86.         pdhStatus = PdhCollectQueryData(hQuery);
    
87.                 Sleep(100);
    
88.         pdhStatus = PdhCollectQueryData(hQuery);
    
89.                 Sleep(100);
    
90.         pdhStatus = PdhCollectQueryData(hQuery);
    
91.                 Sleep(100);
    
92.         pdhStatus = PdhCollectQueryData(hQuery);
    
93.                 Sleep(100);
    
94.         pdhStatus = PdhCollectQueryData(hQuery);
    
95.                 Sleep(100);
    
96.         pdhStatus = PdhCollectQueryData(hQuery);
    
97.                 Sleep(100);
    
98.         pdhStatus = PdhCollectQueryData(hQuery);
    
99.                 Sleep(100);
    
100.         pdhStatus = PdhCollectQueryData(hQuery);
     
101.                 Sleep(100);
     
102.         pdhStatus = PdhCollectQueryData(hQuery);
     
103.                 Sleep(100);
     
104.         pdhStatus = PdhCollectQueryData(hQuery);
     
105.                 Sleep(100);
     
106.         pdhStatus = PdhCollectQueryData(hQuery);
     
107.                 Sleep(100);
     
108.         pdhStatus = PdhCollectQueryData(hQuery);
     
109.                 Sleep(100);
     
110.         pdhStatus = PdhCollectQueryData(hQuery);
     
111.                 Sleep(100);
     
112.         pdhStatus = PdhCollectQueryData(hQuery);
     
113.                 Sleep(100);
     
114.         pdhStatus = PdhCollectQueryData(hQuery);
     
115.         pdhStatus = PdhGetFormattedCounterValue(hCounter,PDH_FMT_LONG,NULL,&pfc);  
     
116. 
     
117. //        pdhStatus = PdhGetFormattedCounterValue(hCounter,PDH_FMT_DOUBLE,&dwOpt,&pfc);  
     
118.         if(pdhStatus == ERROR_SUCCESS) {
     
119.                 if(hQuery) {
     
120. 
     
121.                         PdhCloseQuery(hQuery);
     
122.                 }
     
123.                 //wprintf(L",\"%.20g\n", pfc.doubleValue);
     
124.                 printf("long value is %u\n",pfc.longValue);
     
125.                 //int ret = (int)((pfc.doubleValue*100)+0.5)/100.0;
     
126.                 int ret = (int)(pfc.doubleValue + 0.5);
     
127.                 //printf("ret is %d\n",ret);
     
128.                         return ret;
     
129.         }
     
130.         else
     
131.         {
     
132. 
     
133. 
     
134.                 goto exit_prog;
     
135.         }
     
136. exit_prog:
     
137.         if(hQuery)
     
138.                 PdhCloseQuery(hQuery);  
     
139.         return -1;
     
140. 
     
141. 
     
142. }
     
143. 
     
144. int main(void){
     
145. 
     
146. while (1)
     
147. int ret = getCpuUsage(0);
     
148. return 0;
     
149. 
     
150. 
     
151. }
     

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amoyppa

资源管理器看到的利用率是36%，统计出来的是74左右。系统是多核的。

amoyppa

是不是发错地方了？有人看没人回呀。