The document discusses Java performance, highlighting critical factors such as latency, throughput, and stability, while posing key questions regarding performance testing and strategy. It emphasizes the importance of understanding real-world implications, common pitfalls, and the nuances of Java, including misconceptions about its garbage collector and synchronized methods. Ultimately, it asserts that there is no 'magic bullet' for performance issues, and emphasizes a scientific approach to performance tuning.

1. Java Performance
What’s the big deal?
Trisha Gee, Developer
@trisha_gee
mechanitis.blogspot.com
Wednesday, 17 October 12

2. Who are you and what
do you want?
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3. So, performance....
• Where do I start?
• Things to consider...
• Frequently asked questions
• What Not To Do
• Questions?
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4. Where do I start?
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5. Do you
really
care?
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6. Do you care about...?
• Latency
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7. Do you care about...?
• Throughput
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8. Do you care about...?
• Responsiveness
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9. Do you care about...?
• Stability
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10. Do you care about...?
• Restricted hardware
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11. NFRs Are Not Evil
• 99.99% of all orders processed in less than 10ms
• 7000 tweets per second
• Pages load in less than 0.1 seconds
• Must be able to fail over in less than 10 seconds
• 2000 price updates per second with 99% latency of <10ms
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12. Latency
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13. Latency
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14. Considerations
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15. Cost / Benefit
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16. The Real World
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17. Mechanical Sympathy
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18. Testing
• “Performance” testing
• Load testing
• Red Line / Capacity
• Stress testing
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19. Where are your bottlenecks?
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20. Planning for the Future
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21. Planning for the Future
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22. Planning for the Future
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23. Planning for the Future
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24. Planning for the Future
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25. Compromises
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26. FAQs
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27. Questions
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28. Questions
• Why Java?
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29. Questions
• Why Java?
• How does technology x compare to
technology y?
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30. Questions
• Why Java?
• How does technology x compare to
technology y?
• How can I run multi-threaded / in parallel?
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31. Questions
• Why Java?
• How does technology x compare to
technology y?
• How can I run multi-threaded / in parallel?
• Can I throw more hardware at it?
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32. Questions
• Why Java?
• How does technology x compare to
technology y?
• How can I run multi-threaded / in parallel?
• Can I throw more hardware at it?
• How do I speed up <item out of my control>?
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33. Questions
• Why Java?
• How does technology x compare to
technology y?
• How can I run multi-threaded / in parallel?
• Can I throw more hardware at it?
• How do I speed up <item out of my control>?
• Where’s my magic bullet?
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34. Common Pitfalls
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35. Tune By Gut
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36. Myth Based Development
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37. It Works On My Machine
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38. Misleading Microbenchmarks
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39. Profiler Is God
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40. More Hardware Required
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41. Too Smart For New Hardware
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42. Disregarding the Laws of
Physics
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43. The Never Ending Story
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44. OK fine...
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45. Java Stuff
• The Garbage Collector Is Not Your Enemy
• The JVM Is Smarter Than You
• Synchronized Is Evil
• Don’t Forget The Machine
• ...it might not be your code
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46. In Summary
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47. In Summary
• What is is you really care about?
• The real world matters
• There is no magic bullet
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48. Science, Not Art
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49. Questions?
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50. Resources
• We Don’t Need No Stinkin’ Locks! -
3:45pm (now)
• Are your GC Logs Speaking to You? 3:45pm
(now - typical)
• Martin’s Performance Myths presentation
• Kirk’s Performance Tuning course
• Coding the Architecture
• http://is.gd/javaperf
Wednesday, 17 October 12