Intel® VTune™ Profiler Performance Analysis Cookbook

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ID 766316
Date 9/05/2023
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Document Table of Contents
Document Table of Contents x
Intel® VTune™ Profiler Performance Analysis Cookbook
Intel® VTune™ Profiler Performance Analysis Cookbook x
Methodologies Configuration Recipes Tuning Recipes Notices and Disclaimers
Methodologies x
Top-down Microarchitecture Analysis Method OpenMP* Code Analysis Method Custom Data Collection for Performance Analysis (NEW) Software Optimization for Intel® GPUs (NEW) Core Utilization in DPDK Apps PCIe Traffic in DPDK Apps DPDK Event Device Profiling Effective Utilization of Intel® Data Direct I/O Technology Compile a Portable Optimized Binary with the Latest Instruction Set
Configuration Recipes x
Profiling High Bandwidth Memory Performance on Intel® Xeon® CPU Max Series Profiling Windows* Applications for Hybrid CPU Platforms (NEW) Profiling Machine Learning Applications (NEW) Profiling Single-Node Kubernetes* Applications (NEW) Analyzing Hot Code Paths Using Flame Graphs (NEW) Improving Hotspot Observability in a C++ Application Using Flame Graphs Measuring Performance Impact of NUMA in Multi-Processor Systems Profiling Games built with Unity* (NEW) Profiling Games built with Unreal Engine* (NEW) Profiling Java Applications as a Remote User (NEW) Profiling JavaScript* Code in Node.js* Analyzing CPU and FPGA (Intel® Arria® 10 GX) Interaction Profiling a .NET* Core Application Ingredients Prepare Your Application for Analysis Run Advanced Hotspots Analysis Identify Hotspots in the Managed Code Optimize the Code with Loop Interchange Verify the Optimization See Also Profiling Applications in Amazon Web Services* (AWS) EC2 Instances Enabling Performance Profiling in GitLab* CI Configuring a Hyper-V* Virtual Machine for Hardware-Based Hotspots Analysis Profiling an Application for Performance Anomalies (NEW) Profiling an OpenMP* Offload Application running on a GPU (NEW) Profiling a SYCL* Application running on a GPU Profiling an FPGA-driven SYCL* Application Profiling Hardware Without Intel Sampling Drivers Profiling MPI Applications Profiling Docker* Containers Profiling a Remote Target Through a Proxy Server (NEW) Profiling in a Singularity* Container Profiling Linux*, Android*, and QNX* System Boot Time Using Intel® VTune™ Profiler Server with Visual Studio Code and Intel® DevCloud for oneAPI (NEW) Using Intel® VTune™ Profiler Server in HPC Clusters Using the Command-Line Interface to Analyze the Performance of a SYCL* Application running on a GPU (NEW)
Tuning Recipes x
Cache-Related Latency Issues in Segmented Cache Environment False Sharing Frequent DRAM Accesses Poor Port Utilization Page Faults Instruction Cache Misses Inefficient Synchronization Inefficient TCP/IP Synchronization OS Thread Migration OpenMP* Imbalance and Scheduling Overhead Processor Cores Underutilization: OpenMP* Serial Time Scheduling Overhead in Intel® Threading Building Blocks (Intel® TBB) Apps PMDK Application Overhead
Intel® VTune™ Profiler Performance Analysis Cookbook

Profiling a .NET* Core Application

This recipe uses Intel® VTune™ Profiler for .NET Core dynamic-code profiling to locate performance hotspots in the managed code and optimize the application turnaround.

Ingredients

This section lists the hardware and software tools used for the performance analysis scenario.

  • Application: a sample C# application that adds all the elements of an integer List. The application is used as a demo and not available for download.

  • Tools:

    • Intel® VTune™ Profiler 2018

      NOTE:

      • Starting with the 2020 release, Intel® VTune™ Amplifier has been renamed to Intel® VTune™ Profiler.

      • Most recipes in the Intel® VTune™ Profiler Performance Analysis Cookbook are flexible. You can apply them to different versions of Intel® VTune™ Profiler. In some cases, minor adjustments may be required.

      • Get the latest version of Intel® VTune™ Profiler:

    • .NET Core 2.0 SDK

  • Operating system: Microsoft* Windows* 10

  • CPU: Intel microarchitecture code name Skylake

Prepare Your Application for Analysis

  1. Open a new command window for the .NET environment variables to take effect. Make sure that .NET Core 2.0 is successfully installed: 

    dotnet --version

  2. Create a new listadd directory for the application: 

    mkdir C:\listadd
> cd C:\listadd

  3. Enter dotnet new console to create a new skeleton project with the following structure:

  4. Replace the contents of Program.cs in the listadd folder with C# code that adds the elements of an integer List: 

    using System;
using System.Linq;
using System.Collections.Generic;

namespace listadd
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Starting calculation...");            
            List<int> numbers = Enumerable.Range(1,10000).ToList();
            for (int i =0; i < 100000; i ++)
            {
                ListAdd(numbers);
            }
            
            Console.WriteLine("Calculation complete");            
        }

        static int ListAdd(List<int> candidateList)
        {
            int result = 0;
            foreach (int item in candidateList)
            {
                result += item;
            }
            
            return result;
        }        
    }
}

  5. Create listadd.dll in the C:\listadd\bin\Release\netcoreapp2.0 folder: 

    dotnet build -c Release

  6. Run the sample application: 

    dotnet C:\listadd\bin\Release\netcoreapp2.0\listadd.dll

Run Advanced Hotspots Analysis

  1. Launch VTune Profiler with administrator privileges.

  2. Click the New Project button on the toolbar and specify a name for the new project, for example: dotnet.

  3. In the Analysis Target window, select local host and Launch Application target type from the left pane.

  4. On the Launch Application pane, specify the application to analyze:

    • Application: C:\Program Files\dotnet\dotnet.exe

    • Application parameters: C:\listadd\bin\Release\netcoreapp2.0\listadd.dll

    NOTE:

    The location of dotnet.exe depends on your environment and can be identified with the command: where dotnet.

  5. Click the Choose Analysis button on the right and select the Advanced Hotspots analysis from the left pane.

    NOTE:

    Advanced Hotspots analysis was integrated into the generic Hotspots analysis starting with Intel VTune Amplifier 2019, and is available via the Hardware Event-Based Sampling collection mode.

  6. Click Start to run the analysis.

Identify Hotspots in the Managed Code

When the collected analysis result opens, switch to the Bottom-up tab and set the data grouping level to Process/Module/Function/Thread/Call Stack:

Expanding dotnet.exe > listadd.dll discovers the managed listadd::Program::ListAdd function that took the most CPU Time:

Double-click this hotspot function to open the source view. To view the source and disassembly code side by side, click the Assembly toggle button on the toolbar:

Use the statistics per source line/assembly instruction to identify the most time-consuming code snippets (line 24 in the example above) and work on optimizations.

Optimize the Code with Loop Interchange

VTune Amplifier highlights the following code line as performance-critical:

foreach (int item in candidateList)

For optimization, consider using the for loop statement. Replace the contents of Program.cs with this C# code: 

using System;
using System.Linq;
using System.Collections.Generic;

namespace listadd
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Starting calculation...");            
            List<int> numbers = Enumerable.Range(1,10000).ToList();
            for (int i =0; i < 100000; i ++)
            {
                ListAdd(numbers);
            }
            
            Console.WriteLine("Calculation complete");            
        }

        static int ListAdd(List<int> candidateList)
        {
            int result = 0;
            for (int i = 0; i < candidateList.Count; i++)
            {
                result += candidateList[i];
            }

            return result;
        }        
    }
}

Verify the Optimization

To verify the optimization for the updated code, re-run the Advanced Hotspots analysis.

Before the optimization the sample application took 2.636 seconds of CPU time:

After optimization the application ran for 0.945s, which is a 64% reduction in time over the original:

NOTE:

To discuss this recipe, visit the developer forum

Parent topic: Configuration Recipes
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