Feature #20707: Move `Time#xmlschema` into core

• Status: Open
• Assignee: -
• Target version: -

[byroot (Jean Boussier)]

Performance

Converting Time into RFC3339 / ISO8601 representation is an significant hotspot for application that serialize data in JSON, XML or other formats.

Right now this feature is currently available through the time default gem, so it rely on Time#strftime.
While strftime could certainly be optimized, ultimately it's a very generic API so can't make a lot of assumptions about the output.

Whereas ISO8601 is a very strict format, with very few dynamic part, so it's much easier for dedicated code to be well optimized, as the final size of the string can be computed upfront etc.

I experimented with this and was able to get a ~5x speedup with a fairly straightforward implementation.

compare-ruby: ruby 3.4.0dev (2024-08-29T13:11:40Z master 6b08a50a62) +YJIT [arm64-darwin23]
built-ruby: ruby 3.4.0dev (2024-08-30T13:17:32Z native-xmlschema 34041ff71f) +YJIT [arm64-darwin23]
warming up......

|                        |compare-ruby|built-ruby|
|:-----------------------|-----------:|---------:|
|time._xmlschema         |      1.087M|    5.190M|
|                        |           -|     4.78x|
|utc_time._xmlschema     |      1.464M|    6.848M|
|                        |           -|     4.68x|
|time._xmlschema(6)      |    859.960k|    4.646M|
|                        |           -|     5.40x|
|utc_time._xmlschema(6)  |      1.080M|    5.917M|
|                        |           -|     5.48x|
|time._xmlschema(9)      |    893.909k|    4.668M|
|                        |           -|     5.22x|
|utc_time._xmlschema(9)  |      1.056M|    5.707M|
|                        |           -|     5.40x|

Usability

Aside from the performance reason, ISO8601 is so common that having this functionality built-in without needing to require anything would make sense to me.
xmlschema is the most common reason why I require time, and in many case having it core would allow not to load it at all.