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Performance  - a challenging craft
 

Performance - a challenging craft

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In my talk at socrates 2011, I descrived why performance is a craft and what to do to ensure great performance. I concluded with a few best practies and wonder if there are more

In my talk at socrates 2011, I descrived why performance is a craft and what to do to ensure great performance. I concluded with a few best practies and wonder if there are more

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    Performance  - a challenging craft Performance - a challenging craft Presentation Transcript

    • A Challenging Craft
    • That‘s me My day to day job is to help customers fixing software performance Fabian People really struggle with performance But most of them struggle with coding as well  If creating good software is a craft, performance should be one as well Customer
    •  Some say: „creating software is art“ Art and software development need creativity Art
    •  Fixing performance is often considered magic Magic is something  only you understand  you do in a hard to Magic follow fashion
    •  Correctness in detail Research and verification Craft
    •  All types share  Passion  Learning  Experience Which way?
    •  Value == Money We need a business case for performance Money What is the impact of (in parts of the world) bad performance?
    •  Amazon measured the impact of 100ms delay Sales dropped by 1% In a year that would be Typical (?) retailer 245 Million USD
    •  Instable or slow software delays time to market Slow software is no longer accepted by customers New?
    •  Insurances like to send paper via mail Not meeting deadlines can cause  Legal issues Snail Mail  Canceled contracts  Loss of money
    • Is A Craft
    •  Calculate Execution Time  Code x = 5ms  Code y = 2*x = 10ms Know code in advance Waterfall approach Performance Engineering Proving the performance of software is more difficult than proving the correct function
    •  We prove functional correctness with automated tests High coverage Look closely Run examples and see if they are fast
    •  Done late in project If done at all How much load breaks the system? No chance to fix anything
    •  Avoid human errors Require machine decidable fail / pass check What is the measure? 42cm are fast?
    •  Functionality is independent of the environment Performance characteristics can vary  Unusable slow Our Environment  Lightning fast
    •  Underpowered hardware Loaded with tools and stuff Developers Luckily not the production driving fast environment
    •  More power But also more load How much faster is production than development? Crawling Production Any estimation on how much better or worse the environments are is incorrect
    •  Real performance tests need real systems Test in production Clone production Stop playing infrastructure
    •  Amount of data is unpredictable Application usage is unpredictable Tweets per second How thought of using Twitter for build notification?
    • Dev Prod Test Test1  Fabian Lange Test Test2  Uwe Friedrichsen Test Test3  Mirko Novakovic Showing 3/3  Showing 3/6,434,867
    •  Syntethic load tests are unrealistic No application has hundreds of users doing the same procedure again and again Load Baselines Understanding real load is difficult
    •  Real usage cannot be generated Real usage can be captured & replayed Live Systems are live Be careful 
    •  Continous performance tests Close to real setup App Monitor Observe production behavior Fix issues fast
    •  Conflicting interests  Development: Change  Operations: Stability Another Movement Need to work together
    • Is A Challenge
    •  Can‘t we do anything before production? We want to deliver something, Let users test? which works perfectly!
    •  Optimizations might have no impact Micro-Optimizations are Missed Target dangerous
    •  Soft Measure Works good for code quality Sonar Are there performance best practices?
    •  Yahoo Best Practices Google Best Practices Plenty of tools Good Waterfalls Work well
    •  Naive implementation looks fine But is not multithreaded
    •  This is threadsafe But slow
    •  This is correct Correct synchronisation is hard
    •  Check Log Level (Ugly) Check Log Level (Nicer)
    •  Static SimpleDateFormat is wrong Working with Dates and Calendars is very expensive!
    •  Some people misuse it as loop Results are unexpected behavior or slow execution
    •  Analyzes Java Bytecode Knows 58 Performance Bugs Most are rather trivial Indeed finds bugs
    •  Detecting deadlocks is difficult Many thesiss on deadlock detection Verifies Java Few code
    •  Hidden Gem Tries to cause Deadlocks IBM Support Assistant
    •  We need more and reliable  Code Performance Metrics  Best Practices  Tools
    • Is A Challenging Craft
    • Q&A
    •  Art  YSlow flickr.com/photos/37202375@N03/3490107873 developer.yahoo.com/yslow Magic  Pagespeed flickr.com/photos/princes_milady/4238912548 code.google.com/speed/page-speed Crossroads  Java Locking flickr.com/photos/40481200@N06/4857965280 en.wikipedia.org/wiki/Double-checked_locking Envelopes  PHP Ternary Operator flickr.com/photos/creatingmotherhood/3663914542 fabien.potencier.org/article/48/the-php-ternary- operator-fast-or-not Test flickr.com/photos/cayusa/2159980025  JavaScript for .. In stackoverflow.com/questions/500504/javascript-for- Scales in-with-arrays flickr.com/photos/reinvented/309512320  Findbugs Tape Measure findbugs.sourceforge.net flickr.com/photos/hippie/2466583497  Jlint World jlint.sourceforge.net flickr.com/photos/heimdahlrecounts/4346082743  IBM Multicore SDK Toys www- flickr.com/photos/sbluerock/364123380 01.ibm.com/support/docview.wss?uid=swg21456945 TPS flickr.com/photos/twitteroffice/5681263084 Bananas flickr.com/photos/design-dog/1249337589 Dart flickr.com/photos/malavoda/2369876508