The Unreasonable Effectiveness of Small Optimizations

"The challenge of building large-scale complex systems often gets caught between purist visions that never get off the ground and seemingly pragmatic random-walk tinkering that slowly grinds to a halt via diminishing returns.

If you're ambitious -- and I hope you are for the sake of my own future gig-flow -- sooner or later, whether you are an engineer, designer, project manager, CTO, CMO, VP of Sales, or CEO, you'll run into this challenge. How do you break out of this rock-and-a-hard place impasse? My friend Keith Adams, veteran of several such complex scaling challenges at VMWare, Facebook, and now Slack, pointed out the key insight: what he calls the "unreasonable effectiveness of small optimizations."

I am going to paraphrase the version he shared over lunch at the Facebook campus a few years ago and call it Keith's Law: In a complex system, the cumulative effect of a large number of small optimizations is externally indistinguishable from a radical leap. If you want to do big things in a software-eaten world, it is absolutely crucial that you understand Keith's Law. So let me BIRG in the light of the wisdom of Keith and other great technologists I've had the pleasure of knowing, and unpack it for you. All stupidities and inanities in what follows are mine."


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