Dear all, From www.javaworld.com, I read the paper "Profiling CPU usage from within a Java application,Roll your own CPU usage monitor using simple JNI". Thanks to the source code privided there on the site, I have properly merged the code into my application. That is, I can now get the CPU usage value of the current java program, by a programmatic way, from inside my java program.
But I met a problem: My application runs ok under WindowsXP and Windows2000, but when I run the same code under Windows98, the CPU usage value is very strange and wrong. The following is the snapshot of some of the output: *********************************** CPU utilization: 2147483.647%
CPU utilization: 2147483.647%
CPU utilization: 2147483.647%
CPU utilization: 2147483.647%
*********************************** that is, all the CPU usage value is 2147483.647% , which is of course wrong.
And, to find the reason, I inserted: printf("Hi from fileTimeToInt64(), and _time.QuadPart = %ld \n",_time.QuadPart); in the fileTimeToInt64() function, which produces: ********************************************************************* * Hi from fileTimeToInt64(), and _time.QuadPart = 7253008 Hi from fileTimeToInt64(), and _time.QuadPart = 0 Hi from fileTimeToInt64(), and _time.QuadPart = 1832791420 Hi from fileTimeToInt64(), and _time.QuadPart = 29607974 Hi from fileTimeToInt64(), and _time.QuadPart = 1832791420 Hi from fileTimeToInt64(), and _time.QuadPart = 29607974 Hi from fileTimeToInt64(), and _time.QuadPart = 1832791420 Hi from fileTimeToInt64(), and _time.QuadPart = 29607974 ********************************************************************** that is, after the first time, all the value returned from fileTimeToInt64() are either 1832791420 (by the calling of fileTimeToInt64 (& kernelTime) in getProcessCPUTime() ) or 29607974 (by the calling of fileTimeToInt64 (& userTime) in getProcessCPUTime() ).
To compare, I run the same code under WindowsXP, and got the following output: ********************************************************************** Hi from fileTimeToInt64(), and _time.QuadPart = 3404896 Hi from fileTimeToInt64(), and _time.QuadPart = 10414976 CPU utilization: 7.677%
Hi from fileTimeToInt64(), and _time.QuadPart = 3404896 Hi from fileTimeToInt64(), and _time.QuadPart = 10515120 CPU utilization: 2.115%
Hi from fileTimeToInt64(), and _time.QuadPart = 3404896 Hi from fileTimeToInt64(), and _time.QuadPart = 10815552 CPU utilization: 5.649%
Hi from fileTimeToInt64(), and _time.QuadPart = 3505040 Hi from fileTimeToInt64(), and _time.QuadPart = 10915696 CPU utilization: 3.992%
Hi from fileTimeToInt64(), and _time.QuadPart = 3505040 Hi from fileTimeToInt64(), and _time.QuadPart = 10915696 CPU utilization: 0.0% ********************************************************************** This output under WinXP is right, since we can calculate the CPU usage value from it: take the 5.649% as examlpe: 10815552 + 3404896 = 14220448 10515120 + 3404896 = 13920016
and : 14220448 - 13920016 = 300432 (100ns) and then: 300432 / 10000000 = 0.0300432 (s) 0.0300432 / 0.5 = 0.0600864 6.00% it explains : 5.649% perfectly
But, I wonder what is wrong with the same code under Windows98? Why does it prodeuce strange output value such as: *********************************** CPU utilization: 2147483.647% *********************************** and ************************** ******************************************** Hi from fileTimeToInt64(), and _time.QuadPart = 7253008 Hi from fileTimeToInt64(), and _time.QuadPart = 0 Hi from fileTimeToInt64(), and _time.QuadPart = 1832791420 Hi from fileTimeToInt64(), and _time.QuadPart = 29607974 Hi from fileTimeToInt64(), and _time.QuadPart = 1832791420 Hi from fileTimeToInt64(), and _time.QuadPart = 29607974 Hi from fileTimeToInt64(), and _time.QuadPart = 1832791420 Hi from fileTimeToInt64(), and _time.QuadPart = 29607974 ********************************************************************** ?
and some one pointed to me that: ### If you read the MSDN documentation for GetProcessTimes will learn that the API is
unsupported in Windows 98. The API is present is Kernel32.DLL but does not do anything.
The return values of GetProcessTimes are garbage.
HTH ###
but: thanks for informing me that what should I do now to do the CPU usage work by Java/JNI under Windows 98? is there any workaround?
Thanks in advance!
Best wishes,
Adam
my email add: depender@yahoo.com
Note1: I set the probe interval to 500ms Note2: I monitors the currently running java program's CPU usage value
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