One of the largest performance bottlenecks in Element.getAttribute (and I suspect a bunch of other webidl bindings as well) is copying (often very small) SpiderMonkey strings into heap allocated DOMStrings. It doesn't seem practical to always use JS strings as they don't use UTF-8 and it would require a lot more rooting and generally seems like it would require rewriting a large amount of code. But, it was pointed out that these (often very small) strings are always heap allocated.
See #6906 and specifically these comments: https://github.com/servo/servo/issues/6906#issuecomment-159372789 https://github.com/servo/servo/issues/6906#issuecomment-159379936 https://github.com/servo/servo/issues/6906#issuecomment-159383632 I've created a crate[0] that provides a mostly drop-in replacement of std::string::String but with inline storage for small strings to avoid heap allocation. It also provides a StringExt trait to abstract string operations over both InlinableString and std::string::String. I'm planning on implementing this trait for DOMString as well, making the codegen emit bindings code that uses InlinableString for stack allocated strings, and make the webidl interface methods use `StringExt` instead of `DOMString` directy. My hope is that this will make a good chunk of that performance bottleneck go away. [0] https://github.com/fitzgen/inlinable_string If I bug you on irc with requests for help, please have patience with me :) If you see something architecturally wrong with this plan, please let me know sooner rather than later! Cheers, Nick _______________________________________________ dev-servo mailing list dev-servo@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-servo
