Chapter 6: Analyze the System Program Counter › Description of the Program Counter Analysis Report › PC Samples by System Image

PC Samples by System Image

Use of the /IDENTIFICATION qualifier produces a report page in which statistics under the heading “Filter” pertain to a specific process, rather than the Interrupt Stack. If /IDENTIFICATION is omitted, Filter statistics are for the interrupt stack (no process context).

The example labeled “PC Samples by System Image Report Example” is an example of a PC Sample by System Image report with filter statistics for the interrupt stack.

System Module

This is the name of the system module. The entry “Unknown System Address” can also appear here, meaning that one or more PC samples were found in system virtual address space that did not fall into the range of known address ranges. In addition, the report image reads the system virtual address ranges for the RMS code and for all device drivers and adapter handlers loaded into non-paged pool at the time the collection process was initiated.

Module Samples

The number of PC samples collected in the system virtual address range of the specified system module.

% Total Module Samples

The percentage of PC samples collected in the system virtual address range of the specified system module.

Filter: Process Name

If the /IDENTIFICATION qualifier is used when generating the report, Process Name is that of a specified process. Otherwise, INTERRUPT STACK appears in this heading.

Filter Samples

The number of PC samples collected in the system virtual address range of the specified system module while the process “process name” was the currently executing process. If /IDENTIFICATION was not used when generating the report, the pseudo-process name “INTERRUPT STACK” is listed, and the statistics indicate the number of samples collected while in the system module on the interrupt stack.

% of Module Samples

The percentage of PC samples collected in the system virtual address range of the specified system module while the process “process name” was current. This is calculated as follows:

(Number of filter samples for module)
------------------------------------- x 100
(Number of samples for module)

If /IDENTIFICATION was not used when generating the report, the pseudo-process name “INTERRUPT STACK” is listed, and the statistics indicate the percentage of samples collected while in the system module on the interrupt stack.

% Total Filter Samples

The percentage of PC samples collected in the system virtual address range of the specified system module while the process “process name” was current. This is calculated as follows:

(Number of filter samples for module)
------------------------------------- x 100
(Total number of filter samples)

If /IDENTIFICATION was not used when generating the report, the pseudo-process name “INTERRUPT STACK” is listed, and the statistics indicate the percentage of samples collected while in the system module on the interrupt stack.