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Stephen Belanger authored
This will enable Node.js to get much better performance from async_hooks as currently PromiseHook delegates to C++ for the hook function and then Node.js delegates it right back to JavaScript, introducing several unnecessary barrier hops in code that gets called very, very frequently in modern, promise-heavy applications. This API mirrors the form of the original C++ function based PromiseHook API, however it is intentionally separate to allow it to use JSFunctions triggered within generated code to, as much as possible, avoid entering runtime functions entirely. Because PromiseHook has internal use also, beyond just the Node.js use, I have opted to leave the existing API intact and keep this separate to avoid conflicting with any possible behaviour expectations of other API users. The design ideas for this new API stemmed from discussion with some V8 team members at a previous Node.js Diagnostics Summit hosted by Google in Munich, and the relevant documentation of the discussion can be found here: https://docs.google.com/document/d/1g8OrG5lMIUhRn1zbkutgY83MiTSMx-0NHDs8Bf-nXxM/edit#heading=h.w1bavzz80l1e A summary of the reasons for why this new design is important can be found here: https://docs.google.com/document/d/1vtgoT4_kjgOr-Bl605HR2T6_SC-C8uWzYaOPDK5pmRo/edit?usp=sharing Bug: v8:11025 Change-Id: I0b403b00c37d3020b5af07b654b860659d3a7697 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2759188Reviewed-by: Marja Hölttä <marja@chromium.org> Reviewed-by: Camillo Bruni <cbruni@chromium.org> Reviewed-by: Anton Bikineev <bikineev@chromium.org> Reviewed-by: Igor Sheludko <ishell@chromium.org> Commit-Queue: Camillo Bruni <cbruni@chromium.org> Cr-Commit-Position: refs/heads/master@{#73858}
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