4 ms·
> Performance only goes downhill from here if the function does more work, Should be the opposite. Overhead as a proportion of total time goes down the more us
by jacobolus 4y ago
> Performance only goes downhill from here if the function does more work,
Should be the opposite. Overhead as a proportion of total time goes down the more useful work is involved.
- TylerE 4y agoProportionally sure, but actual wall clock time can only increase.
- jacobolus 4y agoOkay, but the proportion of overhead is what matters here. If you have a CPU or memory size bottleneck and a parallelizable workload, it makes plenty of sense to split the work across multiple machines and coordinate them over the network. If your job was going to take 20 minutes for 1 machine to do and you can fan it out to 100 machines and accomplish the same in 12 seconds per machine plus an extra fraction of a second in communication overhead, that’s a huge win in total latency. The overhead doesn’t matter. If you have a trivial workload that can be handled quickly on one machine, but you unnecessarily add extra network hops and drop your potential throughput by 100x, then it’s a huge loss. A ping server that makes a bunch of international RPC calls before replying is the worst case scenario for overhead.