VTune: Intel’s Visual
Tuning Environment
K. Sridharan, VTune Development Manager
What is VTune?
VTune is a performance tuning environment
for Windows™ developers from Intel.
 VTune is now bundled with:

– Intel C/C++ and FORTRAN compilers
– Intel Performance Library Suite
– Intel Architecture tutorials, Processor Manuals
and Computer Based Training Materials.
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Intel Corporation
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Overview of VTune

VTune is a Performance tuning tool for
Windows 95 and NT* developers to:
Monitor the performance of all active software.
Identify “HotSpots” in a program and analyze its
performance as it executes on an Intel Architecture
microprocessor platform.
Examine each instruction and uncover problems at
machine code level.
Help optimize code using context-sensitive on-line
tuning suggestions.
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Time-Based Sampling

A periodic interrupt drives the Sampling
– Interrupt sources can be VTD, RTC or NMI*.
– Sample data stored in buffer until its full.
– Buffer flush disables sampling during write.

Analyze the sampling data.
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Data consists of cs:eip and module name data.
Match addresses with an application or OS routine.
Sampling data stored in Access 7.0 DB.
Easy to import Sampling data into Excel.
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Event-Based Sampling on
Pentium®Pro Processor

CPU Events report on internal CPU states.
 Event Sampling enabled by CPU and APIC
 VTune helps manage the choices
– Data Cache Misses
– Partial Stall Counts
– Branch Statistics
• Mispredictions and Total Branches Taken
– Clock Count Statistics
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Intel Corporation
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HotSpot Analysis

From the System-wide view, you can zoom into a
specific module of interest.
– Display all of the HotSpots organized by functions in the module,
memory locations, class names and source files.
– For each HotSpot, VTune displays the symbol name, address, and
the number of samples collected.

For detailed information, double click on a HotSpot
to open a source code or assembly view.
The HotSpot view helps you to identify sections in your code
that take the most CPU time and that have potential
performance problems.
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Intel Corporation
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Static Analysis

Shows performance information by
instruction
– Target machine can be different than Host machine.
– Indicates pairing on Pentium® processor, decoder
groups on PentiumPro Processor.
– Shows penalties incurred by the instruction.
– Shows execution clocks or micro-ops.
– Disassembly fits into a Portal which can be moved or
enlarged. Size of Portal affects speed of analysis.
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Intel Corporation
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Dynamic Analysis

Assists in pin-pointing the issues identified
by sampling or static analysis.
 Uses advanced simulator technology to
run, trace and simulate your actual code in
one step
 Fine-tune performance attributes of key
sections of your code, such as:
• Cache behavior analysis
• Branch Prediction results
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Intel Corporation
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VTune’s Code Coaches

C and Fortran Code Coaches offer specific
suggestions on the modifications to
improve performance; Examples:
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•
•
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Loop interchange and loop Invariant code motion
Converts from scalar to mmx using intrinsics calls
Traversing an array/list: binary search, hash tables
Consider using MMX(tm) technology
Consider using Intel’s Performance Libraries.
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Intel Corporation
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Intel Compiler Strategy
 Intel’s
compilers track Intel
microprocessor improvements
 Available as a plug in extension to the
“Microsoft Developer’s Studio”
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Compiler Performance Features
 Profile
guided optimizations
 Floating point optimizations
 Floating point alignment
 MMX™ Technology
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Intel Corporation
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Intel Performance Library Suite
 Signal
Processing Library V3.0
– DSP, Filtering, Transform and Telephony
 Recognition
Primitives Library V3.0
– Voice/Speech Recognition and Processing
 Image
Processing Library V1.0 Beta
– Photo Editing, Enhancement and Transform
 Math
Kernel Library V2.0
– Scientific and Technical Computation
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Intel Corporation
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Why Use Intel’s Performance Libraries ?
 Highly
optimized for performance
 Alternative
for code development
 Stay
current with the latest Intel Architectures
 High
level programming language interface
 Reduce
development effort
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Intel Corporation
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VTune Coming Attractions

VTune Support For Java:
– First release is VTune 2.5:
• view performance in every component: including Java
class files
• call graph
• working with major vendors.
• Beta this month.
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Intel Corporation
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VTune Coming Attractions

VTune 3.0
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Beta later this year.
All OS events (Perfmon) and Events over time
Process, Processor Views.
Call graph
Memory Pattern Analysis
C++/ASM coach
Dynamic Analysis for PII
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Intel Corporation
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Backup Slides
Key Features:
Code Analysis of binary files

Perform code analysis without the need
to create an executable and sample.
 Accepts .exe, .dll or .obj files.
 Zoom into source code by doubleclicking on the desired function from
the summary.
• If no source code is available, the binary is
disassembled.
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Intel Corporation
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Source View

C/C++, FTN or Assembly or ?? displayed.
 Sample times shown by source line.
– Source and disassembly can be intermixed.

Any of these file types can supply symbol
and line number information:
– .SYM, .HDR, .DMP, .DBG, .MAP, .PDB , C7/CV (NB09),
NB10, NB11, FB09, FB0A, DWARF 2.
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Intel Corporation
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Libraries Platform Support
 32-bit
operating system (Microsoft* Win 95 and
Microsoft* Win NT)
 Compiler support
– Multi-Media Libraries (DLLs and Static Libraries)
» Intel C/C++ Compiler Plug-in
» MSVC/C++ V4.x
» Borland V5.0
– Math Kernel Library (Static Libraries)
» Intel Fortran 77 Compiler
» Microsoft Powerstation Fortran V4.0
» Watcom Fortran 77 V10.6
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Multi-Media Library Features

High performance
– Optimized processor specific DLLs and static libraries for :
• Intel 486 TM
• Pentium® Processor
• Pentium® Processor with MMXTM Technology
• Pentium® Pro Processor
• Pentium® II Processor

Scalable architecture
– Processor detection and processor specific DLL loading

C-Callable programming interface

Support for integer and floating point data

Custom DLL Builder for minimum memory footprint
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Intel Corporation
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Math Kernel Library

Workstation technical computing library
– Basic Linear Algebra Subroutines (BLAS)
– Single and double precision FFTs

Main features
– Optimized kernels at every level of BLAS
– Level 3 BLAS multithreaded performance scales on SMP systems
– Optimized for Pentium® Pro Processor
– Interfaces to several FORTRAN compilers
– Static libraries
– DLL will be available
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