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Keynote, LambdaConf 2014 - The Silent Productivity Killer


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My take on what's wrong with the way we program - a sliver of what's wrong anyway.

Published in: Software, Technology
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Keynote, LambdaConf 2014 - The Silent Productivity Killer

  1. 1. The Silent Productivity Killer Paul Phillips Source: It's xkcd, yes.
  2. 2. Ex-Hacker Tells All! • One-time scalac hacker • Now full-time malcontent • Voted Mr. Congeniality by scala community • Zero years in a row (and counting)
  3. 3. Jon Pretty admits it took him 10 years to amass 10 years scala experience. The picture suggests he was enjoying the forty weeks vacation standard in Western Europe. I dub thee Jon Pretty Slow.
  4. 4. < 10 years
  5. 5. Scientifically Determined Facts about me, in the domain of interpersonal orientation
  6. 6. How Software Is Made
  7. 7. Initiate build sequence!
  8. 8. TIME PASSES You're older than you've ever been and now you're even older and now you're even older and now you're even older ! You're older than you've ever been and now you're even older and now you're older still ! -- They Might Be Giants
  9. 9. Hmm, let's try it with that one brick three millimeters to the left.
  10. 10. Wait a Minute • The titular "silent killer" is not the time spent waiting • It is the inhibition of flow state • Outside of flow, you are but a shadow of your best self
  11. 11. Mihaly Csikszentmihalyi (mee-hy cheek-sent-mə-hy-ee) identifies these preconditions for flow: ! 1) Goals are clear 2) Feedback is immediate 3) A balance between opportunity and capacity
  12. 12. The Lag Analogy • Imagine editing system files on a faraway server under a 6 second echo lag. No mistakes! • Is the time to completion only 6 seconds greater? • Is your error rate only "6 seconds" higher? • Is the task only "6 seconds" less enjoyable?
  13. 13. • How often do we tolerate a "6 second lag" when writing code? • To a first approximation: always • Optimistically: way too often The Lag Analogy
  14. 14. The Lag Analogy • "You should have been using screen/tmux!" • Right: why tolerate such uncivilized conditions? • A highly responsive layer coalesces inputs and batches them to the high-latency system • It's madness to have to traverse every requirement to connect cause to effect
  15. 15. What IS a compiler? • Responsiveness is a (or THE) key to a UX • It is mandatory to achieve flow state • We are unwise to turn this critical task over to a general purpose compiler • More responsive does not mean faster: usually it means slower! (i.e. less throughput)
  16. 16. repl startup • Initialize the compiler in a separate thread • Print the prompt immediately • Result: startup feels impossibly faster! • Yet "minimum time to first result" is unchanged • Responsiveness, where perception IS reality
  17. 17. multitasking • scalac is so slow to build, I always had two work trees going simultaneously • Context switching in that codebase is not cheap for the wetware • Incremental compilation is useless in scalac
  18. 18. Interrupting Myself • Everyone seems to agree interruptions are costly • I experience no interruptions - from humans • Flow state is no less elusive for that • "Flow interruptions" are everywhere
  19. 19. "incremental comp..." • Incremental compilation recompiles less (at best) • I say: recompile never! Recompiling is rebooting • First requirement is a functional compiler • And we derive the output from the delta
  20. 20. A change to a base trait may incur the recompilation of over one thousand files. ! The regeneration of 100 MB of class files. ! While the ΔOutput requires writing 4 bytes to a single classfile.
  21. 21. Skeptical Hippo
  22. 22. "that's impossib..." • Yes, very likely it's impossible for scala, and most existing languages • But a language can be engineered around it • And a language SHOULD be engineered around it
  23. 23. "who needs a comp..." • Bad news: most software cannot be reasoned about • Try some pure reasoning against a few scalac bugs • We can design better software, but that won't unwrite the rest of it • And regardless, frobbing knobs and seeing what happens is how most of the humans learn
  24. 24. "The next step is to transfer some psychic energy each day from tasks that we don’t like doing, or from passive leisure, into something we never did before, or something we enjoy doing but don’t do often enough because it seems too much trouble. ! There are literally millions of potentially interesting things in the world to see, to do, to learn about. But they don’t become actually interesting until we devote attention to them." Mihaly Csikszentmihalyi