"terrible" here means within the ballark of Express and usually lower than Phoenix (the Elixir web framework), far slower than Go, and than most Java framework. The source is the TechEmpower framework benchmarks, with the caveat that Vapor isn't in all the categories, and the usual benchmarks caveat.
For why it's not performant, I don't know precisely. Part of it may be because people don't use it a lot on the server side so it's not as optimized as the others. From what I've heard, Swift was also optimized for low memory usage rather than raw speed. Outside of that, I don't know. I would expect it to be around Go.
> From what I've heard, Swift was also optimized for low memory usage rather than raw speed
at a 1000 foot view, Swift inherits its reference counting system from Objective-C, meaning objects are freed immediately when their retain count goes to zero; vs a tracing GC releasing many objects whenever a tracing cycle runs. maintaining reference counts also adds a cost that a different GC approach could avoid. it's true that Swift will maintain a lower memory footprint, potentially at the cost of lower throughput
I would be a little surprised if that explains the bulk of a performance difference though, vs Swift frameworks being newer and less optimized
Zababa|4 years ago
For why it's not performant, I don't know precisely. Part of it may be because people don't use it a lot on the server side so it's not as optimized as the others. From what I've heard, Swift was also optimized for low memory usage rather than raw speed. Outside of that, I don't know. I would expect it to be around Go.
WSSP|4 years ago
at a 1000 foot view, Swift inherits its reference counting system from Objective-C, meaning objects are freed immediately when their retain count goes to zero; vs a tracing GC releasing many objects whenever a tracing cycle runs. maintaining reference counts also adds a cost that a different GC approach could avoid. it's true that Swift will maintain a lower memory footprint, potentially at the cost of lower throughput
I would be a little surprised if that explains the bulk of a performance difference though, vs Swift frameworks being newer and less optimized