3 ms·

Yes. In this discussion and on Reddit, people still talk about binary vs textual as the source of the problem, but I've argued (based on empirical data) that th

Yes. In this discussion and on Reddit, people still talk about binary vs textual as the source of the problem, but I've argued (based on empirical data) that the lexical details are not the reason for the performance problems. Also, Swift is marketed as a fast language (also based on LLVM), yet in my measurements it's 20x to 50x slower than Rust for JSON processing. I found that surprising. Would you not?

mov_ 6y ago
I agree with you, it's weird that Swift JSON is so slow and binary isn't necessarily faster. My exasperation is you were surprised by JSON becoming an issue, when this was the most controversial design decision about the project. To me, it's completely unsurprising.
- __s 6y ago
  They're saying the reasons were surprising, ie they expected it to be controversial for different reasons
shakna 6y ago
It wouldn't be especially surprising to me. JSON's parsing performance is difficult, whether or not the language doing the parsing is fast or not. There's a reason that there are almost always libraries claiming faster JSON performance, regardless of the language. Go is marketed as a fast language, and they're still trying to build a high performance JSON parser [0]. Parsing JSON will always be slower than most of the alternatives. [0] https://dave.cheney.net/high-performance-json.html https://dave.cheney.net/high-performance-json.html
saagarjha 6y ago
Swift’s slowness is kind of unfortunate, although I hear that there is work being gone to remove a lot of the lifetime cruft that was going in behind the scenes to make it slow. And unfortunately I think the primary motivation for Swift’s performance is driven by its primary application, which is UI development, so “good enough” performance usually works…
- pjmlp 6y ago
  WWDC has a couple of talks regarding runtime improvements, and low level coding including unsafe style coding with Swift.

mov_ 6y ago

I agree with you, it's weird that Swift JSON is so slow and binary isn't necessarily faster. My exasperation is you were surprised by JSON becoming an issue, when this was the most controversial design decision about the project. To me, it's completely unsurprising.

__s 6y ago
They're saying the reasons were surprising, ie they expected it to be controversial for different reasons

shakna 6y ago

It wouldn't be especially surprising to me. JSON's parsing performance is difficult, whether or not the language doing the parsing is fast or not. There's a reason that there are almost always libraries claiming faster JSON performance, regardless of the language. Go is marketed as a fast language, and they're still trying to build a high performance JSON parser [0]. Parsing JSON will always be slower than most of the alternatives. [0] https://dave.cheney.net/high-performance-json.html https://dave.cheney.net/high-performance-json.html

saagarjha 6y ago

Swift’s slowness is kind of unfortunate, although I hear that there is work being gone to remove a lot of the lifetime cruft that was going in behind the scenes to make it slow. And unfortunately I think the primary motivation for Swift’s performance is driven by its primary application, which is UI development, so “good enough” performance usually works…

pjmlp 6y ago
WWDC has a couple of talks regarding runtime improvements, and low level coding including unsafe style coding with Swift.