Intel® Advisor Help

Run CPU / Memory Roofline Insights Perspective from Command Line

To plot a Roofline chart, the Intel® Advisor does the following:

  1. Collect OpenCL™ kernels timings and memory data using the Survey analysis with GPU profiling.
  2. Measure the hardware limitations and collect floating-point and integer operations data using the Characterization analysis with GPU profiling.

    Intel® Advisor calculates compute operations (FLOP and INTOP) as a weighted sum of the following groups of instructions: BASIC COMPUTE, FMA, BIT, DIV, POW, MATH.

    Intel Advisor automatically determines data type in the collected operations using the dst register.

Tip

See Intel Advisor cheat sheet for quick reference on command line interface.

Prerequisites

Set Intel Advisor environment variables with an automated script to enable the advisor command line interface (CLI).

Plot a CPU Roofline Chart

There are two methods to run the CPU Roofline. Use one of the following:

Info: In the commands below, make sure to replace the myApplication with your application executable path and name before executing a command. If your application requires additional command line options, add them after the executable name.

Method 1. Run the Shortcut Command

To collect data for a CPU Roofline chart with a shortcut, run the following command:

advisor --collect=roofline --project-dir=./advi_results -– ./myApplication

This command collects data for a basic CPU Roofline chart based on the Cache-Aware Roofline model. You can add other option to the command to collect more data. See Analysis Details below for more options.

Method 2. Run the Analyses Separately

Use this method if you want to analyze an MPI application.

  1. Run the Survey analysis.
    advisor --collect=survey --project-dir=./advi_results -- ./myApplication
  2. Run the Characterization analysis to collect trip counts and FLOP data:
    advisor --collect=tripcounts --flops --project-dir=./advi_results -- ./myApplication

These commands collect data for a basic CPU Roofline chart based on the Cache-Aware Roofline model. You can add other option to the command to collect more data. See Analysis Details below for more options.

You can view the results in the Intel Advisor graphical user interface (GUI), or generate an interactive HTML report. See View the Results below for details.

Analysis Details

The CPU / Memory Roofline Insights workflow includes the following analyses:

  1. Roofline to plot a Roofline chart. This step sequentially runs the Survey and Characterization (trip counts and FLOP) analyses.
  2. Memory Access Patterns (optional) to identify memory traffic data and memory usage issues.
  3. Dependencies (optional) to identify loop-carried dependencies that might limit offloading.

Each analysis has a set of additional options that modify its behavior and collect additional performance data. The more analyses you run and option you use, the more useful data about your application you get.

Consider the following options:

Roofline Options

To run the Roofline analysis, use the following command line action: --collect=roofline.

Note

You can also use this options with --collect=tripcounts if you want to run the analyses separately.

Recommended action options:

Options

Description

--stacks

Enable advanced collection of call stack data. Use this option to get a CPU Roofline with callstacks.

--enable-cache-simulation

Model CPU cache behavior on your target application. Use this option to get a Memory-level CPU Roofline that shows data for all memory levels.

--cache-config=<config>

Set the cache hierarchy to collect modeling data for CPU cache behavior. Use with enable-cache-simulation.

The value should follow the template: [<num_of_caches>]:[<num_of_ways_caches_connected> ]:[<cache_size>]:[<cacheline_size>] for each of three cache levels separated with a /.

--cachesim-associativity=<num>

Set the cache associativity for modeling CPU cache behavior: 1 | 2 | 4 | 8 (default) | 16. Use with enable-cache-simulation.

--cachesim-mode=<mode>

Set the focus for modeling CPU cache behavior: cache-misses | footprint | utilization. Use with enable-cache-simulation.

See advisor Command Option Reference for more options.

Memory Access Patterns Options

The Memory Access Patterns analysis is optional because it adds a high overhead. This analysis does not add more information to the CPU Roofline chart. The results are added to the Refinement report, which you can view from GUI or from CLI. Use it to understand the Memory-Level Roofline chart better and get more detailed optimization recommendations.

To run the Memory Access Patterns analysis, use the following command line action: --collect=map.

Recommended action options:

Options

Description

--select=<string>

Select loops for the analysis by loop IDs, source locations, or criteria such as scalar, has-issue, or markup=<markup-mode>. This option is required.

See select for more selection options.

--enable-cache-simulation

Model CPU cache behavior on your target application.

--cachesim-cacheline-size=<num>

Set the cache line size (in bytes) for modeling CPU cache behavior: 4 | 8 | 16 | 32 | 64 (default) | 128 | 256 | 512 | 1024 | 2048 | 4096 | 8192 | 16384 | 32768 | 65536. Use with enable-cache-simulation.

--cachesim-sets=<num>

Set the cache set size (in bytes) for modeling CPU cache behavior: 256 | 512 | 1024 | 2048 | 4096 (default) | 8192. Use with enable-cache-simulation.

See advisor Command Option Reference for more options.

Dependencies Options

The Dependencies analysis is optional because it adds a high overhead and is mostly necessary if you have scalar loops/functions in your application. This analysis does not add more information to the CPU Roofline chart. The results are added to the Refinement report, which you can view from GUI or from CLI. Use it to get more detailed optimization recommendations.

To run the Dependencies analysis, use the following command line action: --collect=dependencies.

Recommended action options:

Options

Description

--select=<string>

Select loops for the analysis by loop IDs, source locations, criteria such as scalar, has-issue, or markup=<markup-mode>. This option is required.

See select for more selection options.

--filter-reductions

Mark all potential reductions with a specific diagnostic.

See advisor Command Option Reference for more options.

View the Results

Intel Advisor provides several ways to work with the CPU / Memory Roofline Insights results.

View Results in GUI

When you run Intel Advisor CLI, a project is created automatically in the directory specified with --project-dir. All the collected results and analysis configurations are stored in the .advixeproj project, which you can view in the Intel Advisor.

To open the project in GUI, run the following command:

advisor-gui <project-dir>

Note

If the report does not open, click Show Result on the Welcome pane.

You will see the CPU Roofline report that includes:

CPU Roofline report

View an Interactive HTML Report

Intel Advisor enables you to export an interactive HTML report for the CPU Roofline chart, which you can open in your preferred browser and share.

When you open the report, you see the CPU Roofline chart with the selected configuration. In this report, you can:

If you have a Memory-level Roofline report, you can also:

CPU Roofline HTML report

For details on exporting HTML reports, see Work with Standalone HTML Reports.

Save a Read-only Snapshot

A snapshot is a read-only copy of a project result, which you can view at any time using the Intel Advisor GUI. To save an active project result as a read-only snapshot:

advisor --snapshot --project-dir=<project-dir> [--cache-sources] [--cache-binaries] -- <snapshot-path>

where:

  • --cache-sources is an option to add application source code to the snapshot.
  • --cache-binaries is an option to add application binaries to the snapshot.
  • <snapshot-path is a path and a name for the snapshot. For example, if you specify /tmp/new_snapshot, a snapshot is saved in a tmp directory as new_snapshot.advixeexpz. You can skip this and save the snapshot to a current directory as snapshotXXX.advixeexpz.

To open the result snapshot in the Intel Advisor GUI, you can run the following command:

advisor-gui <snapshot-path>

You can visually compare the saved snapshot against the current active result or other snapshot results.

Next Steps

These sections are GUI-focused, but you can still use them to understand the results. For details about the metrics reported, see CPU Metrics.

See Also