Clock-Based Profiling Data

Related Topics:

Choosing the Data to Collect

Collecting clock-based profiles is the first step toward identifying bottlenecks in your program. It identifies functions in which your program is spending most of its time. The clock-based data collected for each profiling interval consists of a set of clock "tick" counts for each microaccounting state maintained by the kernel. These are converted into the following execution-time metrics for each function in the program:

• User CPU time. LWP time spent running in user mode on the CPU.
• Wall time. LWP time spent in thread 1. This is the "wall clock time"
• Total LWP time. Sum of all LWP times.
• System CPU time. LWP time spent running in kernel mode on the CPU or in a trap state.
• Wait CPU time. LWP time spent waiting for the CPU.
• Text page fault time. LWP time spent waiting for a text page.
• Data page fault time. LWP time spent waiting for a data page.
• Other wait time. LWP time spent waiting for a lock or for a kernel page, or time spent sleeping or stopped.

Each record includes a timestamp and the thread and LWP IDs at the time the profile is taken, as well as the array of microaccounting state information.