Code profiling with Xdebug and Kcachegrind

Slides for an uncon talk I gave at phpbnl17

Transcript

1. Robert Basic ~ phpbenelux17
   Code profiling with
   Xdebug and KCachegrind
   Robert Basic
   https://robertbasic.com/
   @robertbasic
   

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2. Robert Basic ~ phpbenelux17
   Tools of the trade
   Xdebug
   ● Not just for debugging
   KCachegrind
   ● Visualizing profiling data
   

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3. Robert Basic ~ phpbenelux17
   What’s the fastest code?
   

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4. Robert Basic ~ phpbenelux17
   The code that’s not called!
   

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5. Robert Basic ~ phpbenelux17
   Number of calls
   

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6. Robert Basic ~ phpbenelux17
   Who’s to blame?
   

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7. Robert Basic ~ phpbenelux17
   Which was called by another method
   

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8. Robert Basic ~ phpbenelux17
   Which was called by another method
   

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9. Robert Basic ~ phpbenelux17
   So many callers!
   

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10. Robert Basic ~ phpbenelux17
    A graph to see it
    

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11. Robert Basic ~ phpbenelux17
    Context to understand it
    

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12. Robert Basic ~ phpbenelux17
    Fix it
    This is really up to you
    

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13. Robert Basic ~ phpbenelux17
    Tips for fixing performance issues
    ● Biggest impact, least effort
    ● Profile after every change
    ● Avoid over-optimizing
    ● Learn to EXPLAIN
    

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14. Robert Basic ~ phpbenelux17
    Tips for using Xdebug and KCachegrind
    ● Xdebug
    – xdebug.profiler_output_dir
    – xdebug.profiler_output_name
    – cachegrind.out.%t.%R
    – Xdebug lies!
    ● KCachegrind
    – Install graphviz
    – Use % relative
    – Turn on Cycle detection
    – Settings > Configure KCachegrind > Annotations > Add source folder
    

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15. Robert Basic ~ phpbenelux17
    Other tools
    ● WinCacheGrind, Webgrind
    ● XHProf
    ● Blackfire.io
    

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16. Robert Basic ~ phpbenelux17
    Thanks!
    Questions?
    

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