Visual Studio Profiler let’s start a profiling session !

Maxime Lemaitre – 23/07/2013

Profiling Tools

• Let developers measure, evaluate, and target performance-related issues in their code

– CPU, Memory, Concurrency, ADO.NET…

• Command-line tools but fully integrated into the IDE

• Since VS 2012, available in Pro Version

• Really powerful tools but poorly documented/blogged

• Needs knowledge on the application and on .net framework

Introduction on MSDN

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Profiling Tools Introduction

Here is the general process :

• Configure the performance session by specifying the profiling method and the data that you want to collect.

• Collect profiling data by running the application in the performance session.

• Analyze the data to identify the performance issue.

• Modify code with the goal to increases the application performance of the code

• Collect profiling data on the changed code, and compare the profiling data of the original and changed data.

• Generate a report that documents the increase in performance.

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Profiling Workflow

There are 4 profiling available methods

• CPU Sampling

– Collects application statistics that are useful for initial analysis and for analyzing CPU utilization issues.

• Instrumentation

– Collects detailed timing data that are useful for focused analysis and for analyzing input/output performance issues.

• .NET Memory Allocation

– Collects .NET Framework memory allocation data by using the sampling profiling method.

• Concurrency

– Collects numeric resource contention data.

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Choosing a Profiling Method

Can be attached to a running process !

The sampling profiling method of the Profiling Tools interrupts the computer processor at set intervals and collects the function call stack.

The profiler analysis determines whether the processor is executing code in the target process. If the processor is not executing code in the target process, the sample is discarded.

• Inclusive samples

– The total number of samples that are collected during the execution of the target function.

– This includes samples that are collected during the direct execution of the function code and samples that are collected during the execution of child functions that are called by the target function.

• Exclusive samples

– The number of samples that are collected during the direct execution of the instructions of the target function.

– Exclusive samples do not include samples that are collected during the execution of functions that are called by the target function.

• Inclusive percent

• Exclusive percent

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Sampling Profiling Method

Too Many Samples ? - Slow piece of code - Too many calls to a piece of code => For sure, there is something to optimize

The instrumentation profiling method of the Profiling Tools records detailed timing information for the function calls, lines, and instructions in the profiled application

The instrumentation method injects code at the start and end of target functions in the profiled binary, and before and after each call by those functions to other functions. The injected code records interval between collects and OS operations.

• Elapsed Inclusive values

– The total time that was spent executing a function and its child functions.

• Elapsed Exclusive values

– The time that was spent executing a function, excluding time that was spent in child functions.

• Application Inclusive values

– The time that was spent executing a function and its child functions, excluding time that was spent in operating system events.

• Application Exclusive values

– The time that was spent executing a function, excluding the time that was spent in child functions and the time that was spent in operating system events.

• Elapsed Inclusive & Exclusive percent

• Application Inclusive & Exclusive percent

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Instrumentation Profiling Method

The .NET memory allocation profiling method of Profiling Tools collects information about the size and number of objects that were created in an allocation or destroyed in a garbage collection and a few additional information.

The memory profiler interrupts the computer processor at each allocation of a .NET Framework object in a profiled application. When object lifetime data is also collected, the profiler interrupts the processor after each .NET Framework garbage collection. The data is aggregated for each profiled function and for each type of object.

• Allocation Data

– Total counts and sizes of the allocated or destroyed memory objects

• Lifetime Data

– Displays the number and size of the objects and the generation when they are reclaimed

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Memory Profiling Method

Resource contention profiling collects detailed call stack information each time competing threads in an application are forced to wait for access to a shared resource.

Resource contention reports display the total number of contentions and the total time that was spent waiting for a resource for the modules, functions, source code lines, and instructions in which the waiting occured.

• Inclusive values

– Contentions that were caused by child functions that were called by the function are included in inclusive values.

• Exclusive values

– Contentions caused by child functions are not included. The exclusive time for the function also includes only the wait times that were caused by statements in the function body.

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Concurrency profiling method

• Adds information to a profiling data file about synchronous ADO.NET calls between an application and a SQL Server database

• Can be added to profiling data that is collected with the sampling, instrumentation, .NET memory, or concurrency methods

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Tier Interaction Hidden profiling method

For example, 1204 requests to the Casino Home Page

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Profiling Quick Start

this often begins with a wizard …

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Profiling Wizard

Profiling Method Targets TIP ? Js ?

• Enables us to configure and start performance sessions

– Created/Filled by Performance Wizard

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Performance Explorer

Session Name

The name of the session. Right-click the session name

to edit the session properties

Targets

Binaries that are to be profiled in the session. Can be a

binary, a VS project, or Web site. Each target have own

Properties.

Reports

Files that are generated for the session. Right-click a

report name to open, remove, or export a profiler data

file. Can compare two profiler data files.

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Profiling…

Pause

suspend data collection

Stop profiling

end the profiling session

When profiling you have nothing to do :

- Let is run for standalone app (Console, Test, ..)

- Navigate between pages/forms (Web Site or Desktop)

1 - Hot Path

branch of your application's call tree that was most active when data was collected

2 - Functions Doing the Most Individual Work.

functions with the highest exclusive samples

3 - Summary Timeline

timeline graph & CPU usage

4 - Error List

uses a set of rules to suggest ways of improving the profiling run and to identify possible performance problems

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Summary View

Summary depends on Profiling method !

There are also a few others Views of profiling data files are displayed

• Call Tree

• Modules View

• Functions View

• Object Lifetime View

• Thread Details View

• Tier Interaction Views

• …

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Analysis Results

Demos

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Demo #1 ASP.NET MVC 4 Sample (Magazine website)

Many Samples in Dal code and many calls to the db. Missing cache ?

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Demo #2 Micro Benchmarking a Translation Helper (in Unit Test)

More than 93% of elapsed time is spent on Regex.Replace … For sure, there is something to improve in the helper.

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Demo #3 Task cancellation Helper

For 100 000 tests, 300 000 tasks were allocated. Ouh ! For sure, memory consumption is not optimal when task is already completed.

• Profiling data can be collected through the ASP.NET profiler when we run a web or a load test

– Limited to sampling and tier interaction data

– Not appropriate for long runs (profiler file can become large …)

• Really powerful if you have real scenarios & test cases

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Profiling ASP.NET Web & Load Tests

You just have to select ASP.NET profiler for your test settings

• Instrumentation profiling can provide a greater level of detail ; this means that more data is collected and instrumentation is more likely to impact the performance

• The Visual Studio profiler provides an API for controlling data collection from within an application

– allow us to limit the amount of data that is collected during a profiling session.

Simply add a reference to Tools\Microsoft.VisualStudio.Profiler.dll

(VSDir\Tools\Performance Tools\)

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Profiler APIs

Right-click a test and choose Profile Test to run performance analysis on a single unit test

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Profiling Unit Tests Since VS 2012 update 2

The test runs as usual followed by the analysis (sampling method).

When analysis completes, you’ll see the classic summary view

Questions ?

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• http://msdn.microsoft.com/en-us/library/ms182372.aspx

• http://msdn.microsoft.com/en-us/library/z9z62c29.aspx

• http://blogs.msdn.com/b/dotnet/archive/2013/04/04/net-memory-allocation-profiling-with-visual-studio-2012.aspx

• http://blogs.msdn.com/b/anilchandra/archive/2012/09/24/test.aspx

• http://blogs.msdn.com/b/visualstudioalm/archive/tags/diagnostics/

• http://blogs.msdn.com/b/dotnet/archive/2013/04/04/net-memory-allocation-profiling-with-visual-studio-2012.aspx

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Appendices & References

Find out more

• On https://techblog.betclicgroup.com/

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