Front End Investigation analysis type uses event-based sampling collection and is targeted for Intel® microarchitectures code name Nehalem/Westmere.
This analysis type presents a breakdown of instruction-delivery-related performance issues. The UOPS_ISSUED.STALL_CYCLES - RESOURCE_STALLS.ANY event evaluates the instruction starvation cycles when you boot the system with the Intel Hyper-Threading Technology (Intel HT Technology) disabled. This problem may result from branch mispredictions causing incorrect instruction "prefetching", micro-operations decoding, resource allocation bandwidth issues, and excessively large binaries.
To see the full list of events used for this analysis type:
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Clik here to view.
New Analysis toolbar button.The Analysis Type window opens.
From the left pane, select Nehalem / Westmere Analysis > Front End Investigation.
The Front End Investigation configuration pane opens on the right. The Details section provides a table with the processor events used for this analysis type.
You can choose to view Front End analysis results in any of the following viewpoints:
Viewpoint | Description |
|---|---|
Hardware Event Counts | Displays the event count for all collected processor events. While the Hardware Event Sample Counts viewpoint provides the actual number of samples collected for an event, Hardware Event Count viewpoint estimates the number of times this event occurred during the collection. |
Hardware Event Sample Counts | Displays the sample count for all collected processor events. While the Hardware Event Counts viewpoint estimates the number of times an event occurred during the collection, the Hardware Event Sample Counts viewpoint provides the actual number of samples collected for this event. |
Hardware Issues | Helps identify where the application is not making the best use of available hardware resources. This viewpoint displays metrics derived from hardware performance counters. Hover over the highlighted metrics values in the grid to read why the extreme value might represent a performance problem. |
Hotspots | Helps identify hotspots - code regions in the application that consume a lot of CPU time. |
Task Time | Visualizes tasks, logical units of work on specific threads, based on ITT API annotations. Identify tasks with the highest execution time and analyze threads responsible for a particular task. |
These viewpoints may include the following windows:
Summary window displays statistics on the overall application execution.
Bottom-up window displays performance data per metric (event ratio/event count/sample count) for each hotspot function.
Top-down Tree window displays hotspot functions in the call tree, performance metrics for a function only (Self value) and for a function and its children together (Total value).
PMU Events window displays count for PMU events selected for the analysis.
Uncore Events window displays count for uncore events selected for the analysis. If there are no uncore events, the upper pane of the window is empty.
Tasks, Tasks over Time, and Tasks by Threads windows provide details on tasks specified in your code with the Task API.