Home » Software Development » Lies, statistics and vendors

About Peter Lawrey

Peter Lawrey

Lies, statistics and vendors

Overview

Reading performance results supplied by vendors is a skill in itself.   It can be difficult to compare numbers from different vendors on a fair basis, and even more difficult to estimate how a product will behave in your system.

Lies and statistics

One of the few quotes from University I remember goes roughly like this:

 

Peak Performance – A manufacture’s guarantee not to exceed a given rating
— Computer Architecture, A Quantitative Approach. (1st edition)

At first this appears rather cynical, but over the years I have come to the conclusion this is unavoidable and once you accept this you can trust the numbers you get in if you see them a new light.

Why is it so hard to give a trustworthy performance number?

There are many challenges in giving good performance numbers.  Most vendors try harder to give trustworthy numbers but it is not as easy as it looks.
  • Latencies and throughputs don’t follow a normal distribution which is the basis of mathematically rigorous statistics.  This means you are modelling something for which is isn’t a generally accepted mathematical model.
  • There are many different assumptions you can make, ways to test your solution and ways to represent the results.
  • You need to use benchmarks to measure something, but those benchmarks are either a) not standard, b) not representative of your use case, or c) can be optimised for in ways which don’t help you.
  • Vendors understand their products and sensibly select the best hardware for their product.  This works best if you only have one product to consider. Multi-product systems many not have an optimal hardware solution for all the products, even if your organisation allowed you to buy the optional hardware.
  • It is easy to report the best results tested and not include results which were not so good.

Any decent vendor will use their benchmarks to optimise their solution.  The downside of this is that the solution will have been optimised more for the benchmarks they report than use cases the vendor hasn’t tested e.g. your use case.

BTW: I often find it interesting to see what use cases the vendor had in mind when they benchmark their solutions.  This can be a good indication of a) what it is good for, b) the assumptions made in designing the solution, and c) how it is generally used already.

Should we ignore all benchmarks?

This can lead people to give up on micro-benchmarks and benchmarks in general because they have been “lied” to many times before.
However, used correctly benchmarks can be a good guide even if they cannot give you definitive or completely reliable answers.  As such I suggest you should be highly sceptical that small difference in performance give you any indication of what you would expect tot see, and only take note of wide variations in performance. By wide variations I mean 3 to 10 times differences.

Percentiles for latency

Customers generally remember the worst service they ever got and take the average service for granted.  When looking at the latency of your systems, it is generally the higher latencies which cause the most issues if not customer complaints.
A common approach for modelling the distribution of latencies is to sort all the latencies and report a sample of the worst.

 

PercentileOne in NScaleNotes
50%“typical”
 1x
This is a good indication of what is possible.
It is the most optimistic figure you could use
90%one in
ten
2x-3x
This is a better indication of performance
if tested on a real, complex system.
99%one in
100
4x-10x
For benchmarks of simplified systems, this is a better
indication of what you can realistically expect to achieve
99.9%one in
1,000
10x-30x
For benchmarks of simplified systems, this is a conservative
indication of what you can expect.
99.99%one in
10,000
20x-100xThis number is nice to have but difficult to reproduce,
even for the same benchmark, let alone for a different use case.
See below
99.999%one in
100,000
varies
This number is almost impossible reproduce between systems.
See below

 

Generally speaking, the latencies escalate geometrically, as you get into the higher percentiles. The very high percentiles have limited value as you have to take more samples to get a reproducible number even on the same system from one day to next.  They can vary dramatically based on the use case or system.

A guide to the number of samples you need for reproducible numbers

Java has a additional feature that it gets faster as it warms up.  In the past I have advocated removing these warm-up figures, but given micro-benchmarks give overly optimistic figures, I am more inclined to include them if for no other reason than it is simpler. My rule of thumb for reproducible percentile figures is that for 1 in N, you need N^1.5 samples for simple micro-benchmarks and N^2 samples for complex systems.

PercentileOne in NSimple test
samples
Complex test
samples
90%one in ten~ 30~ 100
99%one in 100~ 300~ 10,000
99.9%one in 1,000~ 30,000~ 1 million
99.99%one in 10,000~1 million~ 100 million
99.999%one in 100,000~ 30 million~ 10 billion
99.9999%one in 1,000,000~ one billion~ one trillion
Maximum or 100%
never
Infinite
Infinite

Based on this rule of thumb I don’t believe a real maximum can be measured empirically. Never the less, not reporting it all isn’t satisfactory either.  Some benchmarks report what is the “worst in sample” which is better than nothing, but very hard to reproduce. To mitigate the cost of warm up in real systems, I suggest latency critical classes should be pre-loaded, if not warmed up on start up of your application.

In summary

If you are looking for a performance figure you can use, I suggest using the 99 percentile as a good indication of what you can expect in a real system.  If you want to be cautious, use the 99.9 percentile. If this number is not given, I would assume you might get about 10x the average or typical latency and 1/10th of the throughput the vendor can get under ideal conditions.  Usually this is still more than enough. If the vendor quotes performance figures close to what you need, or worse doesn’t quote figures at all, beware !! I am amazed how many vendors will say they are fast, quick, fastest, efficient, high performance but don’t quote any figures at all.
 

Reference: Lies, statistics and vendors from our JCG partner Peter Lawrey at the Vanilla Java blog.

Do you want to know how to develop your skillset to become a Java Rockstar?
Subscribe to our newsletter to start Rocking right now!
To get you started we give you our best selling eBooks for FREE!
1. JPA Mini Book
2. JVM Troubleshooting Guide
3. JUnit Tutorial for Unit Testing
4. Java Annotations Tutorial
5. Java Interview Questions
6. Spring Interview Questions
7. Android UI Design
and many more ....
Email address:

Leave a Reply

Be the First to Comment!

avatar
  Subscribe  
Notify of
Want to take your Java skills to the next level?
Grab our programming books for FREE!
Here are some of the eBooks you will get:
  • Spring Interview QnA
  • Multithreading & Concurrency QnA
  • JPA Minibook
  • JVM Troubleshooting Guide
  • Advanced Java
  • Java Interview QnA
  • Java Design Patterns
The Spring Framework Cookbook
  • Learn the best practices of the Spring Framework
  • Build simple, portable, fast and flexible JVM-based systems and applications
  • Explore specific projects like Boot and Batch
The Spring Data Programming Cookbook
  • Learn how to use data access technologies and cloud-based data services
  • Set up the environment and create a basic project
  • Learn how to handle the various modules (e.g. JPA, MongoDB, Redis etc.)
The Selenium Programming Cookbook
  • Kick-start your own projects using this testing framework for web applications
  • Learn JUnit integration and Standalone Server functionality
  • Find out the most popular Interview Questions about the Selenium Framework
The Mockito Programming Cookbook
  • Kick-start your own web projects using this open source testing framework
  • Write simple test cases using the Mockito Framework
  • Learn how to integrate with JUnit, Maven and other frameworks
The JUnit Programming Cookbook
  • Learn basic usage and configuration of JUnit
  • Create multithreaded tests
  • Learn how to integrate with other testing frameworks
The JSF 2.0 Programming Cookbook
  • Build component-based user interfaces for web applications
  • Set up the environment and create a basic project
  • Learn Internationalization and Facelets Templates
The Amazon S3 Tutorial
  • Develop your own Amazon S3 based applications
  • Learn API usage and pricing
  • Get your own projects up and running in minimum time
Java Design Patterns
  • Learn how Design Patterns are implemented and utilized in Java
  • Understand the reasons why patterns are so important
  • Learn when and how to apply each one of them
Java Concurrency Essentials
  • Dive into the magic of concurrency
  • Learn about concepts like atomicity, synchronization and thread safety
  • Learn about testing concurrent applications
The IntelliJ IDEA Handbook
  • Kick-start your own programming projects using IntelliJ IDEA
  • Learn how to setup and install plugins
  • Create UIs with this Java integrated development environment
The Git Tutorial
  • Learn why Git differs from other version control systems
  • Explore Git's usage and best practises
  • Learn branching strategies
The Eclipse IDE Handbook
  • Explore the most widely used Java IDE
  • Learn how to setup and install plugins
  • Built your own projects up and running in minimum time
The Docker Containerization Cookbook
  • Explore the world’s leading software containerization platform
  • Learn how to wrap a piece of software in a complete filesystem
  • Learn how to use DNS and various commands
Developing Modern Applications With Scala
  • Develop modern Scala applications
  • Build SBT and reactive applications
  • Learn about testing and database access
The Apache Tomcat Cookbook
  • Explore Apache Tomcat open-source web server
  • Learn about installation, configuration, logging and clustering
  • Kick-start your own web projects using Apache Tomcat
The Apache Maven Cookbook
  • Explore the Apache Maven build automation tool
  • Learn about Maven's project structure and configuration
  • Learn about Maven's dependency management and plug-ins
The Apache Hadoop Cookbook
  • Explore the Apache Hadoop open-source software framework
  • Learn distributed caching and streaming
  • Kick-start your own web projects using Apache Hadoop
The Android Programming Cookbook
  • Explore the Android mobile operating system
  • Learn about services and page views
  • Learn about Google Maps and Bluetooth functionality
The Elasticsearch Tutorial
  • Explore the Elasticsearch search engine
  • Develop your own Elasticsearch based applications
  • Learn operations, Java API Integration and reporting
Amazon DynamoDB Tutorial
  • Develop your own Amazon DynamoDB based applications
  • Learn DynamoDB Concepts and Best Practices
  • Get your own projects up and running in minimum time
Java NIO Programming Cookbook
  • Learn features for intensive I/O operations
  • Follow a series of tutorials on Java NIO examples
  • Get knowledge on Java Nio Socket and Asynchronous Channels
JBoss Drools Cookbook
  • Explore Drools business rule management system
  • Follow a series of tutorials on Drools examples
  • Get knowledge on business rules for a shopping domain model
Vaadin Programming Cookbook
  • Explore Vaadin web framework for rich Internet applications
  • Learn the Architecture and Best Practices
  • Get knowledge on Data Binding and Custom Components
Groovy Programming Cookbook
  • Explore Apache Groovy object-oriented programming language
  • Create sample applications and explore interview questions
  • Get knowledge on Callback functionality and various widgets
GWT Programming Cookbook
  • Explore the open source Google Web Toolkit
  • Create sample applications and explore interview questions
  • Create and maintain complex JavaScript front-end applications in Java
Do you want to know how to develop your skillset to become a Java Rockstar?
Subscribe to our newsletter to start Rocking right now!
To get you started we give you our best selling eBooks for FREE!
1. JPA Mini Book
2. JVM Troubleshooting Guide
3. JUnit Tutorial for Unit Testing
4. Java Annotations Tutorial
5. Java Interview Questions
and many more ....
Email address:
Do you want to know how to develop your skillset to become a Java Rockstar?
Subscribe to our newsletter to start Rocking right now!
To get you started we give you our best selling eBooks for FREE!
1. JPA Mini Book
2. JVM Troubleshooting Guide
3. JUnit Tutorial for Unit Testing
4. Java Annotations Tutorial
5. Java Interview Questions
and many more ....
Email address:
Do you want to know how to develop your skillset to become a Java Rockstar?
Subscribe to our newsletter to start Rocking right now!
To get you started we give you our best selling eBooks for FREE!
1. JPA Mini Book
2. JVM Troubleshooting Guide
3. JUnit Tutorial for Unit Testing
4. Java Annotations Tutorial
5. Java Interview Questions
6. Spring Interview Questions
7. Android UI Design
and many more ....
Email address:
Want to be a DynamoDB Master ?
Subscribe to our newsletter and download the Amazon DynamoDB Tutorial right now!
In order to help you master this Amazon NoSQL database service, we have compiled a kick-ass guide with all the major DynamoDB features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Programming Interview Coming Up?
Subscribe to our newsletter and download the Ultimate Multithreading and Concurrency interview questions and answers collection right now!
In order to get you prepared for your next Programming Interview, we have compiled a huge list of relevant Questions and their respective Answers. Besides studying them online you may download the eBook in PDF format!
Email address:
Java Interview Coming Up?
Subscribe to our newsletter and download the Ultimate Spring interview questions and answers collection right now!
In order to get you prepared for your next Java Interview, we have compiled a huge list of relevant Questions and their respective Answers. Besides studying them online you may download the eBook in PDF format!
Email address:
Java Interview Coming Up?
Subscribe to our newsletter and download the Ultimate Java interview questions and answers collection right now!
In order to get you prepared for your next Java Interview, we have compiled a huge list of relevant Questions and their respective Answers. Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Java NIO Master ?
Subscribe to our newsletter and download the Java NIO Programming Cookbook right now!
In order to help you master Java NIO Library, we have compiled a kick-ass guide with all the major Java NIO features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Drools Master ?
Subscribe to our newsletter and download the JBoss Drools Cookbook right now!
In order to help you master Drools Business Rule Management System, we have compiled a kick-ass guide with all the major Drools features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be an iText Master ?
Subscribe to our newsletter and download the iText Tutorial right now!
In order to help you master iText Library, we have compiled a kick-ass guide with all the major iText features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be an Elasticsearch Master ?
Subscribe to our newsletter and download the Elasticsearch Tutorial right now!
In order to help you master Elasticsearch search engine, we have compiled a kick-ass guide with all the major Elasticsearch features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Scala Master ?
Subscribe to our newsletter and download the Scala Cookbook right now!
In order to help you master Scala, we have compiled a kick-ass guide with all the basic concepts! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a JUnit Master ?
Subscribe to our newsletter and download the JUnit Programming Cookbook right now!
In order to help you master unit testing with JUnit, we have compiled a kick-ass guide with all the major JUnit features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Amazon Web Services ?
Subscribe to our newsletter and download the Amazon S3 Tutorial right now!
In order to help you master the leading Web Services platform, we have compiled a kick-ass guide with all its major features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Spring Framework ?
Subscribe to our newsletter and download the Spring Framework Cookbook right now!
In order to help you master the leading and innovative Java framework, we have compiled a kick-ass guide with all its major features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Eclipse IDE ?
Subscribe to our newsletter and download the Eclipse IDE Handbook right now!
In order to help you master Eclipse, we have compiled a kick-ass guide with all the basic features of the popular IDE! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master IntelliJ IDEA ?
Subscribe to our newsletter and download the IntelliJ IDEA Handbook right now!
In order to help you master IntelliJ IDEA, we have compiled a kick-ass guide with all the basic features of the popular IDE! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Docker ?
Subscribe to our newsletter and download the Docker Containerization Cookbook right now!
In order to help you master Docker, we have compiled a kick-ass guide with all the basic concepts of the Docker container system! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to create a kick-ass Android App ?
Subscribe to our newsletter and download the Android Programming Cookbook right now!
With this book, you will delve into the fundamentals of Android programming. You will understand user input, views and layouts. Furthermore, you will learn how to communicate over Bluetooth and also leverage Google Maps into your application!
Email address:
Want to be a GIT Master ?
Subscribe to our newsletter and download the GIT Tutorial eBook right now!
In order to help you master GIT, we have compiled a kick-ass guide with all the basic concepts of the GIT version control system! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Hadoop Master ?
Subscribe to our newsletter and download the Apache Hadoop Cookbook right now!
In order to help you master Apache Hadoop, we have compiled a kick-ass guide with all the basic concepts of a Hadoop cluster! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Spring Data ?
Subscribe to our newsletter and download the Spring Data Ultimate Guide right now!
In order to help you master Spring Data, we have compiled a kick-ass guide with all the major features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to create a kick-ass Android App ?
Subscribe to our newsletter and download the Android UI Design mini-book right now!
With this book, you will delve into the fundamentals of Android UI design. You will understand user input, views and layouts, as well as adapters and fragments. Furthermore, you will learn how to add multimedia to an app and also leverage themes and styles!
Email address:
Want to be a Java 8 Ninja ?
Subscribe to our newsletter and download the Java 8 Features Ultimate Guide right now!
In order to get you up to speed with the major Java 8 release, we have compiled a kick-ass guide with all the new features and goodies! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Java Annotations ?
Subscribe to our newsletter and download the Java Annotations Ultimate Guide right now!
In order to help you master the topic of Annotations, we have compiled a kick-ass guide with all the major features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a JUnit Master ?
Subscribe to our newsletter and download the JUnit Ultimate Guide right now!
In order to help you master unit testing with JUnit, we have compiled a kick-ass guide with all the major JUnit features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Java Abstraction ?
Subscribe to our newsletter and download the Abstraction in Java Ultimate Guide right now!
In order to help you master the topic of Abstraction, we have compiled a kick-ass guide with all the major features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to master Java Reflection ?
Subscribe to our newsletter and download the Java Reflection Ultimate Guide right now!
In order to help you master the topic of Reflection, we have compiled a kick-ass guide with all the major features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a JMeter Master ?
Subscribe to our newsletter and download the JMeter Ultimate Guide right now!
In order to help you master load testing with JMeter, we have compiled a kick-ass guide with all the major JMeter features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Servlets Master ?
Subscribe to our newsletter and download the Java Servlet Ultimate Guide right now!
In order to help you master programming with Java Servlets, we have compiled a kick-ass guide with all the major servlet API uses and showcases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a JAXB Master ?
Subscribe to our newsletter and download the JAXB Ultimate Guide right now!
In order to help you master XML Binding with JAXB, we have compiled a kick-ass guide with all the major JAXB features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a JDBC Master ?
Subscribe to our newsletter and download the JDBC Ultimate Guide right now!
In order to help you master database programming with JDBC, we have compiled a kick-ass guide with all the major JDBC features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a JPA Master ?
Subscribe to our newsletter and download the JPA Ultimate Guide right now!
In order to help you master programming with JPA, we have compiled a kick-ass guide with all the major JPA features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Hibernate Master ?
Subscribe to our newsletter and download the Hibernate Ultimate Guide right now!
In order to help you master JPA and database programming with Hibernate, we have compiled a kick-ass guide with all the major Hibernate features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a JSF Master ?
Subscribe to our newsletter and download the JSF 2.0 Programming Cookbook right now!
In order to get you prepared for your JSF development needs, we have compiled numerous recipes to help you kick-start your projects. Besides reading them online you may download the eBook in PDF format!
Email address:
Want to be a Java Master ?
Subscribe to our newsletter and download the Advanced Java Guide right now!
In order to help you master the Java programming language, we have compiled a kick-ass guide with all the must-know advanced Java features! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Java Master ?
Subscribe to our newsletter and download the Java Design Patterns right now!
In order to help you master the Java programming language, we have compiled a kick-ass guide with all the must-know Design Patterns for Java! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be a Hadoop Master ?
Subscribe to our newsletter and download the Hadoop Tutorial right now!
In order to help you master Apache Hadoop, we have compiled a kick-ass guide with all the basic concepts of a Hadoop cluster! Besides studying them online you may download the eBook in PDF format!
Email address:
Want to be an Elastic Beanstalk Master ?
Subscribe to our newsletter and download the Amazon Elastic Beanstalk Tutorial right now!
In order to help you master AWS Elastic Beanstalk, we have compiled a kick-ass guide with all the major Elastic Beanstalk features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Amazon Elastic Beanstalk Tutorial
  • Develop your own Amazon Elastic Beanstalk based applications
  • Learn Java Integration and Command Line Interfacing
  • Get your own projects up and running in minimum time
Want to take your Java skills to the next level?
Grab our programming books for FREE!
Here are some of the eBooks you will get:
  • Spring Interview QnA
  • Multithreading & Concurrency QnA
  • JPA Minibook
  • JVM Troubleshooting Guide
  • Advanced Java
  • Java Interview QnA
  • Java Design Patterns
Insiders are already enjoying weekly updates and complimentary whitepapers!
Join them now to gain exclusive access to the latest news in the Java world, as well as insights about Android, Scala, Groovy and other related technologies.
Email address:
Want to be an ActiveMQ Master ?
Subscribe to our newsletter and download the Apache ActiveMQ Cookbook right now!
In order to help you master Apache ActiveMQ JMS, we have compiled a kick-ass guide with all the major ActiveMQ features and use cases! Besides studying them online you may download the eBook in PDF format!
Email address:
Apache ActiveMQ Cookbook
  • Explore Apache ActiveMQ Best Practices
  • Learn ActiveMQ Load Balancing and File Transfer
  • Develop your own Apache ActiveMQ projects