2024-06-28
“Back-of-the-envelop calculations”, “napkin-math”, “latency numbers every programmer should know” - yes, those numbers that usually come up during system design interview questions. This came into my periphery again while looking at RDMA latency checks and benchmarks with P4d instances in AWS (using SoftRoCE). As an old-timer with (most likely) outdated ideas about system design-related latency numbers, although I’m quite familiar with Jeff Dean’s “Numbers every one should know” approximations, I noticed that in a jiffy, I’m still (unconsciously) subscribed to the idea that disk access is most definitely faster than network. Somewhere along the lines of L* cache > memory > disks > network. Come to think of it, not really sure why. It’s probably because pre-cloud, I really didn’t have access to high tier network bandwidth, so my experience with only crappy networks has been etched in my mind for the longest time. This is usually evident when I do quick, back-of-my-head latency calculations of a potential system to design. Of course in the end, benchmarking will have the last say when it comes to these numbers, but having a rough idea of the performance numbers pre-implementation is always helpful.
Infra · Infra · Latency · System-Design
3 minutes