Death notice: Moore’s Law. 19 April 1965 – 2 January 2018

Done in by the weaponisation of optimisation, and now 2017 may be as good as it ever got

DEATH NOTICE

Long beloved by both engineers and computer scientists because of ongoing performance benefits ceaselessly and seemingly effortlessly achieved. From the age of fifty, Moore’s Law began to age rapidly, passing into senescence and then, at the beginning of this month, into oblivion. Moore’s Law leaves a thriving multi-trillion dollar global semiconductor and electronics industry, along with a growing set of questions about how that industry will survive its passing. In lieu of flowers, donations should be lavished on Intel shares.

The death of Moore’s law is no surprise, because the semiconductor industry has told contradictory stories for years. While it created new process nodes like clockwork, the capital requirements to develop those new devices climbed nearly exponentially.

The laws of physics were to blame: they created a money pit into which Intel and the other companies threw tens of billions of dollars, with little to show for it.

Physics was a tough enough opponent, but now computer science itself has joined the fight thanks to the Meltdown and Spectre design flaws first revealed here in The Register.

The two mistakes mean that branch prediction techniques, designed to further improve the performance of ever-cheaper silicon, have introduced two classes of security threats - one set (Meltdown) that can be remediated by imposing as much as a 30% performance penalty - and another set (Spectre) that at this point can’t really be remediated at all - except, possibly, by littering code with instructions that suck all the benefits out of branch prediction.

The computer science behind microprocessor design has therefore found itself making a rapid U-turn as it learns that its optimisation techniques can be weaponised. The huge costs of Meltdown and Spectre - which no one can even guess at today - will make chip designers much more conservative in their performance innovations, as they pause to wonder if every one of those innovations could, at some future point, lead to the kind of chaos that has engulfed us all over the last weeks.

One thing has already become clear: in the short term, performance will go backwards. The steady and reliable improvements every software engineer could rely on to make messy code performant can no longer be guaranteed. Now the opposite applies: it’s likely computers will be less performant a year from now.

Hammered by the finance of physics and the weaponisation of optimisation, Moore’s Law has hit the wall, bounced off - and reversed direction. We’re driving backwards now: all things IT will become slower, harder and more expensive.

That doesn’t mean there won’t some rare wins - GPUs and other dedicated hardware have a bit more life left in them. But for the mainstay of IT, general purpose computing, last month may be as good as it ever gets.

Going forward, the game changes from “cheaper and faster” to “sleeker and wiser”. Software optimisations - despite their Spectre-like risks - will take the lead over the next decades, as Moore’s Law fades into a dimly remembered age when the cornucopia of process engineering gave us everything we ever wanted.

From here on in, we’re going to have to work for it. ®




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