alt Hacker NewsThe corresponding concept in gears is to avoid meshing two gears unless the number of teeth are co-prime, because this will cause uneven wear patterns. If the tooth counts are coprime, then each tooth will contact every tooth on the other gear the same number of times, effectively "wear leveling" the teeth.
In this instance, one fix is to fire the timer every 59.XXX seconds, so it will naturally drift out of phase with the minute hand of the clock.
If work needs to be done exactly every 60 seconds, this is fixed by having a WAIT(RAND(60e6)) microseconds during the first timer initialization, so if 10,000 units start simultaneously they don't try all at once. This is good practice in most (all?) systems. Hint: test power and infra outage/reconnect, which can unintentionally sync timers.
This is why many software will do automated updates every 17 hours: 17 is coprime with 24.
Classic "thundering herd" mitigation tactics.
Edit: Tempting to blame IoT, but (since this is news) I don't think anyone knew there was something to fix here. We have the tools however.
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59 seconds will still have second alignment. Maybe it needs to be prime milliseconds or microseconds.
Small nit: Wait(50+rand(10)) is probably closer to what you want to get about a minute between executions. As stated your proposed execution has an average about 30s execution interval with a variance of about 17s. If you’re talking about a random sleep on a 1 minute interval, this actually results in a possibility of 120s between tasks, also not what you want.
But yeah, as soon as you start using Rand most people make all sorts of mistakes. And if you’re using C Rand, don’t. It has other statistical problems.
Coprime meaning "no common factors".
I get a disturbing amount of equipment that does not take into account the inrush current of starting many loads at the same time. While each individual device is protected by a breaker that can handle the inrush of it's load the main breaker for the equipment is not sized to handle every load starting at the same time. The fix is to include logic that starts things up one at a time but convincing engineers, project managers, and machine owners that they didn't think of everything is an uphill battle.