NIITCERTIFICATE

This is to certify that this report titled

“Intel VTune”

Embodies the original work done by

“Tukuna rout ”

In partial fulfillment of their course

requirement at NIIT.

Registration No: R1100A8700000 Signature of the Co-ordinator

Semester: 3rd ( )

Batch code-B110000

Date: 09 Dec 2010

Acknowledgment

I am also grateful to our faculty Mr. Ashis Ranjan Jena for his keen guidance and support while documentation of this document.And convey my thanks to him for helping me with his kind co-operation and in completion of this report.

And at last I would like to say a special thanks to NIIT who provides us a wonderful chance to present this document in front of all.

With regards

TUKUNA ROUT

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DECLARATION

Hereby I declare that this ISAS report named as “INTEL VTUNE

PERFORMANCE ANALYZER SAMPLING” is a copy containing the

original work done under the supervision of Mr. Ashis Ranjan Jena.

My work can be confirmed from Mr. Ashis Ranjan Jena at any

time. It has never been presented before anywhere. Under any

circumstance, if any material found resembling with copy is truly a

case of co-incident.

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Contents at Glance

Introduction of Inte VTune

Sampling

- Introduction

- Sampling mechanism

- Diff.between TBS & EBS

- What happens during Sampling

- Features of Sampling

- Sampling Over Time

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Introduction“Intel VTune is software from Intel Corporation that is

used by the development companies to analyze their softwares and applications performance.It also provides boost performance of applications, on specific OS.” Intel VTune Performance analyzer is a commercial application for software performance analysis for Intel-manufactured x86 and x64 based machines, and has both GUI and command line interfaces. It is available for both Linux and Microsoft Windows operating systems.

The VTune analyzer provides an integrated performance analysis and tuning environment that helps you analyze your code's performance. It can plug in into Microsoft Visual Studio and Eclipse integrated development environments.

One can work with the VTune analyzer using the graphical interface and command line interface. All commands to create and run Activities must be preceded by Virtual time line at the command line.

LINUX SUPPORT

The VTune(TM) Performance Analyzer can analyze the performance of Linux applications.This is installed on a controlling system and controls the run of your Linux application on a Remote Agent system. The VTune analyzer then collects data on your Linux application by collecting data remotely.

JAVA SUPPORT

When the VTune(TM) Performance Analyzer analyzes the performance of Java application or applet (.class), the Virtual Machine (VM) and Just-in-Time Compiler (JIT) are enhanced to provide the VTune analyzer with specific information required to analyze the performance of a Java application.

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During sampling, the VM and JIT provide the VTune analyzer with information about JIT-compiled Java methods being loaded into memory, such as their memory addresses, sizes, and symbol information.

.NET SUPPORT

The VTune(TM) Performance Analyzer also enables to profile .NET and ASP.NET web services running on the machine.This sets the necessary environment variables and restarts the web service before collecting sampling or call graph data. The environment variables will be deleted and the service is restarted on completing data collection.

FEATUERS OF INTEL VTUNE PERFORMANCE ANALYZER

1. SAMPLING :-

Calculates the actual performance of an application over a period (Time-based sampling) and for various processor events (Event-based sampling).

2. CALL GRAPH :-

Provides a graphical view of the application and helps you identify critical functions and timing details in the application.

3. COUNTER MONITOR:-

Provides system level performance, such as resource consumption, during the execution of an application.

4. TUNING ASSISTANT :-

Provides tuning advice from an anzlusis of the performance data. The tuning advice helps you improve performance of an application.

Sampling

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Sampling is the process of collecting a set of data for analysis and representing the analyzed data in a statistical format. Using the collected data to identify the critical processes, threads, modules, functions, and lines of code running on system.During sampling, the VTune(TM) Performance Analyzer monitors all the software executing on your system including the operating system, JIT-compiled Java applications, .NET applications, and device drivers.

Sampling does not modify binary files or executables in order to monitor the performance of application. The VTune analyzer analyzes the collected samples and helps you to identify:-

1. Hotspots - It is a section of code within a module that takes long time to execute. This results in high amount of processor time spent executing that section, thus generating lot of samples for that module.

2. BottleNecks - It is an area in the code that is slowing down the execution of application. Bottlenecks appear as hotspots in hotspot view. Removing bottlenecks and hotspots optimize the application.

SAMPLING MECHANISM

i. TIME-BASED SAMPLING (TBS): The VTune(TM) uses the operating system timer to interrupt and collect samples of all active instruction addresses at a regular time interval (1ms. by default). The collected samples provides the performance data of all the processes running on the system. Processes that took the longest time to execute have the highest number of samples.

ii. EVENT-BASED SAMPLING (EBS): Use to identify system-wide software performance problems caused by processor events, such as Cache Misses and Mispredicted Branches.From the EBS data, one can determine which process, thread, module, function, and source line in program generated the most processor events, and if any of those events impacted the performance of program. The VTune analyzer provides predefined event ratios recommended for use by performance analysts at Intel.

DIFFERENCES BETWEEN TBS AND EBS

TBS- Data is collected using OS timer. And OS timer is not affected during HLT instructions. And the samples are collected accuratelty. TBS can potentially gives more accurate data.

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EBS– Data is collected using Clocktick events. But when HLT instructions are executed by processor clock, the processor clock causes the clockticks events to stop occurring. This results in no samples being collected while the processor is in halt state. The VTune will report few samples than you were expected.

WHAT HAPPENS DURING SAMPLING

When you run an Activity configured with the sampling collector, the VTune analyzer does the following:

Waits for the delay sampling time (if specified) to elapse and then starts collecting samples.

Interrupts the processor at the specified sampling interval and collects samples of instruction addresses. For every interrupt, the VTune analyzer collects one sample.

Stores the execution context of the software currently executing on system.

FEATURES OF SAMPLING

The following are the main features of the sampling:

1.Collection :-

Multiple event sampling. Perform event based sampling with multiple events in one run. Depending on the type of processor using, the VTune analyzer can monitor and collect samples on two or more events in one run.

Remote sampling. Collect sampling data for an application running on a remote system. Your remote system can be a machine running on any operating system supported by the VTune analyzer.

Collect sampling. Data for applications running on systems enabled with Hyper-Threading Technology.

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2. Views

Thread view.  View the threads running within a process and select one or more threads to drill down to specific hotspots.

Summary view. Opens default for clocktick events. Process view. Display a system-wide view of all the processes

running on your system when sampling data was collected. Module view. Display all the modules within selected threads.

3. Accessories

The following panels and toolbar options are available from the sampling view:

Sampling toolbar. A sampling toolbar is available at the top of each sampling view. This toolbar includes buttons labeled Process, Thread, Module, Hotspot, and Source. Select items within a view and click one of the buttons to drill down.

Tabbed windows. When you open a specific sampling view, a tab is created at the bottom of the window labeled with the name of the view, for example, Process, Thread, Module or Hotspot. If you open several views, a tab for each open view is created at the bottom of the window. You can use the tabs to quickly move from one view to another.

Microsoft Excel. Display your sampling data in a Microsoft Excel 2000 spreadsheet. You can customize the appearance of the spreadsheet report as needed.

Selection Summary panel. View/hide a panel displaying the events configured in an Activity and the number of samples collected per event for the items you select in a view.

Legend. Display a detailed legend for all sampling views. Each Activity result, event, and event ratio is color-coded. The legend explains what each color represents.

Event summary panel. Display the total number of events collected for items you select in a view.

Multi-processor. Display the workload as distributed across multiple processors.

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SAMPLING OVER TIME

1. The Over time view displays the samples collected for single event.

2. It enables you to identify which threads are running serially and in parallel at any point of time.

3. Sampling over Time view can be invoked for Thread, Process and Module views.

4. Sampling over time view consists of two panels. The left panel displays the names of the selected items and the right panel displays the samples collected over time. The right panel is divided into squares, each square representing a unit of time in seconds.

5. The color of the squares indicates the number of samples collected for that unit of time. A red square indicates a large number of samples, and a green square indicates a small number of samples.

The Over Time view can be used to gather the following information:

Context Switching: One can determine if there is excessive context switching.

Processor Utilization: Enables you to view whether processor is idle or not. If sytem process receives samples there is scope for improving processor utilization at that time.

Temporal loction of hotspots: We can see the specific periods of time when a large number of events occur.

Thread Interaction: You can view the pattern of thread behavior and thread interaction.

Viewing the footprint of each thread: You can view the footprint of each thread on Hyper-Threading technology enabled processors.

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