Once threads of interest have been identified using tprof data, they can be mapped to javacores from the same time to determine what was causing the CPU usage. The following details how to complete that mapping process for different versions of WebSphere Application Server.
Resolving the problem
Threads of interest should first be identified using the following TechNote:
How to interpret tprof data for WebSphere Application Server on AIX
Once the threads of interest have been identified, the mapping process is quite simple:
The Thread ID (TID) found in the tprof data is a decimal number. This TID can be mapped to the native ID found in the javacore by simply converting the decimal number to hexadecimal.
For example, from the tprof data a TID 958881 was identified as a thread of interest. Converting this decimal number to hexadecimal, a native ID value of EA1A1 is found. Searching the javacore for this native ID value yields the following:
"Gc Slave Thread" (TID:0x1155D0200, ... native ID:0x0000EA1A1)
This indicates that the thread of interest with a tprof TID of 958881 and a javacore native ID of EA1A1 is entitled "Gc Slave Thread".
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