Instruction-based profiling (IBS) is similar to Event-based profiling (EBP). It collects data based on how a program behaves on processors and memory. This section demonstrates how to configure CodeAnalyst to collect an instruction-based sampling profile.
To collect an Instruction-Based Sampling profile:
Instruction-based sampling produces a broad range of information about program behavior in a single run. IBS fetch samples provide information about instruction fetch while IBS op samples provide information about the execution of operations (ops) that are issued from AMD64 instructions. Several views provide a more focused look at different aspects of fetch and execution behavior.
The "All Data" view displays sample counts for all IBS-derived events. Predefined views are provided to narrow down the displayed performance data to the most useful groups of IBS-derived events.
Use the drop-down list of views to select a different view of the IBS data. (The drop-down list is located next to the Manage button.) Choose IBS fetch instruction cache to see a summary of IBS attempted fetches, completed fetches, instruction cache (IC) misses and the IC miss ratio.
Choose IBS All ops from the drop-down list. This view provides a summary of the number of all IBS op samples, IBS branch (BR) samples and IBS load/store samples that were collected.
Choose IBS MEM data cache from the drop-down list. This view displays the number of load and store operations that were samples, the number of IBS data cache (DC) miss samples, the DC miss rate (DC misses divided by the number of IBS op samples), and the DC miss ratio (DC misses divided by the number of IBS load/store operations).
The Manage button can be used to further customize the IBS derived events that are shown in a view. Using the Manage button is optional. See View Management for more information.
To change the type of data displayed in the current view, click Manage. The View Management dialog box opens. Refer to the View Management section for details. The items listed in the Columns part of the View Management dialog box depend on the view configuration that is currently open for use.
The predefined profile configuration named "Instruction-Based Sampling" collects both IBS fetch and op data. It also uses a sampling period of 250,000 for both IBS fetch sampling and IBS op sampling. The way IBS data is collected can be changed by editing the current profile (data collection) configuration.
To change the way Instruction-Based Sampling data is collected:
The Session settings dialog box appears.
The Edit IBS configuration dialog box appears.