Applied Software Performance Engineering Presented By Steve ...

Applied Software Performance Engineering Presented By Steve Feldman April 13, 2005

Welcome
Session Objectives:
Introduction to Software Performance Engineering
Understanding the SPE Methodology
Applying SPE to Building Block® Development
Performance Analysis Tools
Innovation
Thinking about Performance Early in the Lifecycle
Results/Outcomes
A new approach to design and development

Introduction: About Your Presenter
What do I do at Blackboard?
Director, Software Performance Engineering and Architecture
Part of Product Development, but interface with every department in Blackboard.
A few key points…
Been at Blackboard since the Fall of 2003.
Worked on AP2, AP3 and R7.0
Manage a team of (4) developer/engineers.

Introduction to SPE
Q: What is software performance?
A: Any characteristic of a software product that you could quantifiably measure?
Q: Why is software performance important?
A: The world we live in today is becoming more digitally sophisticated. We expect our digital transactions to be faster then our paper transactions.
Q: How do we manage performance in the SDLC?
A: Plan, Predict, Prove, Improve performance throughout the SDLC?

Introduction to SPE Complete End to End Performance Engineering Refactoring and Optimizing End to End Performance Testing Modeling, Profiling and Simulation Data Collection & Usage Analysis Strategy, Methodology and Best Practices SPE Methodology

Introduction to SPE
Performance is at the top of everyone’s mind.
If Performance is poor, software adoption will decline and potentially cause usage attrition or adoption of alternative products/processes.
Performance Failures cost institutions a large amount of unplanned money.
Performance problems can create a huge trust barrier between user and provider of technology.
So then what is SPE?

Introduction to SPE
SPE is a methodology that…
Provides a systematic, quantitative approach to constructing software systems that meet performance objectives.
Provides a software-oriented approach to architecture, design and implementation choices.
Prescribes principles and performance patterns for creating responsive software.
Performance antipatterns for recognizing and correcting common problems, the data required for evaluation, procedures for obtaining performance specifications, and guidelines for the types of evaluation to be conducted at each development stage.

Introduction to SPE
SPE is a Seven Step Methodology focused primarily on solving the software performance model.
The software performance model consists of optimizing the design patterns and implementation of the underlying code for the greatest performance impact.
Identifying and refactoring software anti-patterns for performance gain.
Included in this methodology is an understanding in solving the system performance model.
The system performance model consists of optimizing the configuration and deployment options of a system in order to yield the greatest performance impact without software modifications.
Making the user experience (response time) more optimal.

Understanding the SPE Methodology Assess Performance Risk Identify Critical Use Cases Select Key Performance Scenarios Establish Performance Objectives
Assessing the performance risk at the outset of the project (During Requirements)
Identify, qualify and mitigate
Look for use cases where there is a risk that, if performance goals are not met, the system will fail or be less than successful
Critical actions important to responsiveness as seen by the user
Most frequently executed scenarios, or those that are critical to the perceived performance of the system.
Each performance scenario corresponds to a workload.
Specify the quantitative criteria for evaluating the performance characteristics of the system under development.
Determine Software Resource Requirements
Determination of software resource utilization (business logic execution) to appropriately measure effect of software as it scales in usage.
Identification of Performance Anti-Patterns targeted for refactoring.
Determine System Resource Requirements
Determination of system resource requirements utilized by the software under a given workload.
Used for sizing and capacity models.
Construct Performance Models - Modeling techniques for representing the software processing steps for the performance model. * SPE Methodology, Dr. Connie Smith and Dr. Lloyd Williams

SPE: Assessing Risk
Distinguish between new development and refactoring.
Work with requirements specialists to understand the problem/domain issues for the development.
Understand potential inter- versus intra-system integration.
Apply common sense and basic business logic from past experiences and similar development projects.

SPE: Identify Critical Use Cases
Most important operations/actions in the feature or system to be developed.
Responsiveness driven.
Risk driven.
You look for use cases where there is a risk that, if performance goals are not met, the system will fail or be less than successful.

SPE: Select Key Performance Scenarios
Unlikely that all critical use cases will be important to performance.
The key performance scenarios are those that are executed frequently, or those that are critical to the perceived performance of the system.
Each performance scenario corresponds to a workload.
Performance scenarios represented through sequence diagrams augmented with some useful extensions.

SPE: Establish Performance Objectives
Identify and define performance objectives.
Specify the quantitative criteria for evaluating the performance characteristics of the system under development.
Response time, throughput, or constraints on resource usage
Identify and define workload objectives.
Specify the level of usage for the scenario.
They are specified as an arrival rate (e.g., number of Web site hits per hour), number of concurrent users or number of parallel transactions.

SPE: Performance Modeling
Use of Execution Graphs to represent software processing steps in the performance model.
The sequence diagram representations of the key performance scenarios are translated into execution graphs.
Reverse Engineer  Reverse Engineer  Reverse Engineer

SPE: Determine Software Resource Requirements
Understand at an atomic level the types of software resource requirements.
Method Calls
SQL Executions
Data Loading
Caching
Understand the effects of this software to inter- and intra-system components.
Understand at best- and worst-case perspective.
90% of the time
Peak time.

SPE: Resource Requirements
Apply Workload Understanding
Based on findings in the software resource requirements phase you should be able to understand at an atomic level...
CPU Cycles consumed by the method call and/or sql operation.
Network overhead (packet transfer)
Memory requirements
Processing Thread/DB Connection Requirements

Applying SPE to Blackboard Building Block Development: Software Performance Requirements
What’s the intended audience of the function?
What’s the frequency of use of the function?
How many touch points (integration)?
What is the function doing?
Processing/Transacting?
Navigating?
Calculating?
Loading?
How much data is the function working with?
What’s the integrity of the transaction?
Candidate for asynchronous processing?
What’s the response time expectation of the user?
What’s the resource requirements to perform the function?

Applying SPE to Blackboard Building Block Development: Software Design
Data Model
Size (number of entity types in the model)
Growth/Capacity (volume driven by usage)
Complexity (relationships, opacity of values)
Input/Validation (internationalized, user provided)
Statistics impact (data that affects the stats schema)
Data Access
Frequency (page-level, session-level, cacheable)
Volatility (same parameters?)
Volume (Small, medium, large datasets? Entity size?)
Complexity (Number of joins? Outer joins?)
File System
Traceability
Requirements
Verification/Testability
Workflow (s)
Breadth. Number of discrete paths.
Depth. How many steps are in each path or branch?
Complexity. Average number of branches.
Testability
Encapsulation. How does a requirements specification point map to a unit test?
Coverage. What function points can’t reasonably be tested at the unit test level?
Instrumentation. Can the design accommodate instrumentation to help testing?
Function Points/Unit Tests

Applying SPE to Blackboard Building Block Development: Iterative Software Development
Software Development is an Iterative Process
Develop for Functionality
Focus on agility
Eloquence Comes through Iterations
Identify Optimal Performance Patterns
Eliminate Unnecessary Performance Anti-Patterns
Profile and Instrument
Refactor Based Findings

Software Development is an Iterative Process
Be willing to scrap your development efforts between iterations.
Focus on simplicity
Complexity comes from a lack of understanding of what it is you are designing or developing.
Decompose your development efforts into manageable components

Applying SPE to Blackboard Building Block Development: Iterative Software Development Spread the load when possible by processing conflicting loads at different times or in different places. Distribution of Processing Execute processing in parallel (only) when the processing speedup offsets the communication overhead and resource contention delays. Streamlining Share resources when possible. When exclusive access is required, minimize the sum of the holding time plus the scheduling time. Distribution of Resources Minimize the product of processing times frequency. Processing versus Frequency Create actions, functions and results that are close to physical computer resources. Location Identify the dominant workload functions and minimize their processing. Centering Instrument systems as you build them to enable measurement and analysis of workload scenarios, resource requirements, and performance objective compliance. Instrumentation Defined specific, quantitative, measurable performance objectives for performance scenarios. Empirical Summary Concept

A pattern is a common solution to a problem that occurs in many different contexts.
Patterns capture knowledge about “best practices” in software design for reuse and application.
Antipatterns are similar to design patterns in that they document recurring solutions to common design problems.
Antipatterns produce negative consequences.
Antipatterns document common mistakes made during software development.

Performance Analysis Tools
Tools for Different Purposes
Modeling/Diagramming
Entity Relationships, Activity and Deployment
Developing
IDE (Eclipse)
Textual Editing
Load Generation
Grinder, Apache JMeter and Volano
Loadrunner, Segue
Profiling
Application Layer
JProbe, Performasure, OptimizeIt, Wily Enterprise, HPJmeter
Database Layer
Hotsos, IronEye, Built-in Blackboard Profiling

Thank You For Participating
Innovating Together in ‘05:
Performance is at the top of everyone’s mind.
Design for Performance
Develop for Performance
Pattern Identification
Antipattern Identification
Profile/Instrument
Resources Available:
www.cmg.org
www.perfeng.com
www.acm.org
Follow up Contact(s):
Steve Feldman (sfeldman@blackboard.com)
IF YOU ONLY REMEMBER 1 THING:
Performance should not be an afterthought, but an upfront effort.

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