Intel® Advisor Help
Vectorization and Code Insights perspective includes several analyses that you can run depending on the desired result. The main analysis is the Survey, which collects performance data for loops and functions in your application and identifies under-vectorized and non-vectorized loops/functions. The Survey analysis is enough to get the basic insights about your application performance.
Set Intel Advisor environment variables with an automated script to enable the command line interface (CLI).
Run the Survey analysis:
advisor --collect=survey --project-dir=<project-dir> -- <target-application> [<target-options>]
Survey analysis collects useful data about your application performance and loop/function vectorization. Explore the Survey results to understand if you need to run other analyses.
Run the Characterization analysis to collect trip counts and/or FLOP data:
advisor --collect=tripcounts [--flop] [--stacks] [--enable-data-transfer-analysis] --project-dir=<project-dir> -- <target-application> [<target-options>]
where:
--flop is an option to collect data about floating-point and integer operations, memory traffic, and mask utilization metrics for AVX-512 platforms.
--stacks is an option to enable advanced collection of callstack data.
--enable-cache-simulation is an option to enable modeling cache behavior.
Optional: Mark up loops for the next analyses to decrease overhead:
advisor --mark-up-loops --project-dir=<project-dir> --select=<criteria> -- <target-application> [<target-options>]
where --select=<string> is an option to select loops for the analysis by loop IDs, source locations, criteria such as scalar, has-issue, or markup=<markup-mode>.
For details about markup, see Loop Markup to Minimize Analysis Overhead.
Optional: Run the Memory Access Patterns analysis to collect memory traffic data and memory usage issues that can slow down loops vectorization:
advisor --collect=map --project-dir=<project-dir> [--select=<criteria>] [--enable-cache-simulation] -- <target-application> [<target-options>]
where:
--select=<string> is an option to select loops for the analysis by loop IDs, source locations, criteria such as scalar, has-issue, or markup=<markup-mode>. For example, use the --select=has-issue to analyze loops that have Possible Inefficient Memory Access Pattern issue. Use this option if you did not run the --mark-up-loops command or want to analyze other loops.
--enable-cache-simulation is an option to enable modeling more accurate memory footprints, cache miss information, and cache line utilization.
Optional: Run the Dependencies analysis to check for loop-carried dependencies that may prevent vectorizing the code:
advisor --collect=dependencies --project-dir=<project-dir> [--select=<string>] [--filter-reductions] -- <target-application> [<target-options>]
where:
--select=<string> is an option to select loops for the analysis by loop IDs, source locations, criteria such as scalar, has-issue, or markup=<markup-mode>. For example, use the --select=has-issue to analyze loops that have Vector Dependence Prevent Vectorization issue. Use this option if you did not run the --mark-up-loops command or want to analyze other loops.
--filter-reductions is an option to mark all potential reductions with a specific diagnostic.
See advisor Command Line Interface Reference for more options.
Example
Run the Survey analysis, Characterization analysis to collect trip count and FLOP metrics, and analyze memory access patterns for loops/functions with the Possible Inefficient Memory Access Patter issue.
advisor --collect=survey --project-dir=./advi -- myApplication
advisor --collect=tripcounts --project-dir=./advi --flop --stacks --enable-data-transfer-analysis -- myApplication
advisor --collect=map --project-dir=./advi --select=has-issue -– myApplication
Intel Advisor provides several ways to view the Vectorization and Code Insights results.
View Result in CLI
You can print the results collected in the CLI and save them to a .txt, .csv, or .xml file.
Run the following command:
advisor --report=<analysis-type> --project-dir=<project-dir> --format=<format>
where:
<analysis-type> is the analysis you want to generate the results for. For example, survey for the Survey report, top-down for the Survey report in a top-down view, map for the Memory Access Patterns, or dependencies for the Dependencies report.
--format=<format> is a file format to save the results to. <format> is text (default), csv, xml.
See advisor Command Line Interface Reference for more options.
For example, to generate the Survey report:
advisor --report=survey --project-dir=./advi
You should see a similar result:
ID Function Call Sites Total Self Type Why No Vectorization Vector ISA Compiler Average Min Max Call Count Transformations Source Location Module and Loops Time Time Estimated Gain Trip Count Trip Count Trip Count __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 14 [loop in main at mmult_serial.cpp:79] 0.495s 0.495s Vectorized Versions 1 vectorization possible but seems inefficient... SSE2 <2.42x 127; 127; 1; 7 127; 127; 1; 7 128; 128; 1; 7 524252; 524324; 530432; 530432 Interchanged; Unrolled mmult_serial.cpp:79 1_mmult_serial.exe 6 -[loop in main at mmult_serial.cpp:79] 0.275s 0.275s Vectorized (Body) SSE2 2.42x 127 127 128 524252 Unrolled; Interchanged mmult_serial.cpp:79 1_mmult_serial.exe 3 -[loop in main at mmult_serial.cpp:79] 0.205s 0.205s Vectorized (Body) SSE2 2.42x 127 127 128 524324 Unrolled; Interchanged mmult_serial.cpp:79 1_mmult_serial.exe 7 -[loop in main at mmult_serial.cpp:79] 0.015s 0.015s Peeled 1 1 1 530432 Interchanged mmult_serial.cpp:79 1_mmult_serial.exe 11 -[loop in main at mmult_serial.cpp:79] 0s 0s Remainder vectorization possible but seems inefficient... 7 7 7 530432 Interchanged mmult_serial.cpp:79 1_mmult_serial.exe 4 [loop in main at mmult_serial.cpp:79] 0.510s 0.015s Scalar inner loop was already vectorized 1024 1024 1024 1024 Interchanged mmult_serial.cpp:79 1_mmult_serial.exe 12 [loop in main at mmult_serial.cpp:79] 0.510s 0s Scalar Versions 1 inner loop was already vectorized 1024 1024 1024 1 mmult_serial.cpp:79 1_mmult_serial.exe 5 -[loop in main at mmult_serial.cpp:79] 0.510s 0s Scalar inner loop was already vectorized 1024 1024 1024 1 mmult_serial.cpp:79 1_mmult_serial.exe
The result is also saved into a text file advisor-survey.txt located at <project-dir>/eNNN/hsNNN.
advisor --report=joined --report-output=<path-to-csv>
where --report-output=<path-to-csv> is a path and a name for a .csv file to save the report to. For example, /home/report.csv. This option is required to generate a joined report.
See CPU and Memory Metrics for more information about the metrics reported.
View Result 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, that you can view in the Intel Advisor.
To open the project in GUI, you can run the following command:
advisor-gui <project-dir>
You first see a Vectorization Summary report that includes the overall information about vectorized and not vectorized loops/functions in your code and the vectorization efficiency, including:
Performance metrics of your program and the speedup for the vectorized loops/functions
Top five time-consuming loops and top five optimization recommendations with the highest confidence
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.
Continue to Find Loops that Benefit from Better Vectorization to understand the results. For details about the metrics reported, see CPU and Memory Metrics.