Memory Access analysis type uses event-based sampling collection and is targeted for the Intel® microarchitectures code name Sandy Bridge.
This analysis type uses events that provide a breakdown of cache traffic due to loads and an overview of total off-core traffic. Explore this data to understand a memory access pattern and get a direction to its optimization.
Memory Access analysis monitors traditional Cycles and Instructions Retired events and, for example, events that enable detecting data sharing by cores of the same processor.
Due to two latency thresholds set up for Memory Access analysis, it enables monitoring LLC hits and LLC misses simultaneously with a reasonable statistical accuracy.
Most of the collected events used in Memory Access analysis are precise. This simplifies understanding the data access pattern. Off-core traffic is divided into the local DRAM and remote DRAM accesses. Typically, you should focus on minimizing remote DRAM accesses that usually have a high cost.
To see the full list of events used for this analysis type:
Click the
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(standalone GUI)/![]()
(Visual Studio IDE) New Analysis toolbar button.The Analysis Type window opens.
From the left pane, select Microarchitecture Analysis > CPU Specific Analysis > Sandy Bridge Analysis > Memory Access.
The Memory Access configuration pane opens on the right. The Details section provides a table with the processor events used for this analysis type.
(standalone GUI)/
(Visual Studio IDE) New Analysis toolbar button.You can choose to view Memory Access 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. |
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 pane 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).
Caller/Callee window displays parent and child functions of the selected focus function. This window is available only if stack collection was enabled during analysis configuration.
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.