Facebook 推出了 Hermes,為了 React Native 而生的 JS Engine

Facebook 提供了一個對 React Native 最佳化的 JS engine:「Hermes: An open source JavaScript engine optimized for mobile apps, starting with React Native」。

裡面有提到兩個比較重要的的部份是 No JIT 與 Garbage collector strategy,針對行動裝置的特性而設計:避免 JIT 產生的 overhead,以及降低記憶體使用量。

官方給的改善主要也都是偏這兩塊:

不過沒有提到 CPU usage 會上升多少,只是帶過去:

Notably, our primary metrics are relatively insensitive to the engine’s CPU usage when executing JavaScript code.

對於 Facebook 也許是可以接受的數量,但對於其他人就沒概念了... 要入坑的人自己衡量這部份的風險 XD

PHP 的 JIT 翻修計畫

在「JIT for PHP project」這邊看到 PHP 新的翻修計畫:

I'm glad to say that we have started a new JIT for PHP project and hope to deliver some useful results for the next PHP version (probably 8.0).

We are very early in the process and for now there isn't any real performance improvement yet. So far we spent just 2 weeks mainly working on JIT infrastructure for x86/x86_64 Linux (machine code generation, disassembling, debugging, profiling, etc), and we especially made the JIT code-generator as minimal and simple as possible. The current state, is going to be used as a starting point for research of different JIT approaches and their usability for PHP.

不知道會帶來多少效能提昇 :o

Webkit 推出 B3 JIT Compiler (Bare Bones Backend)

Webkit 推出了 B3 加快 optimization 的速度,取代原來 LLVM 的工作:「Introducing the B3 JIT Compiler」。

在文章後方 Performance Results 的部份可以看到最主要的差異在啟動時間:

另外也可以看到其他各種 performance benchmark 也幾乎都是小勝 LLVM。

接下來會有 ARM64 與其他平台的計畫:

B3 is not yet complete. We still need to finish porting B3 to ARM64. B3 passes all tests, but we haven’t finished optimizing performance on ARM. Once all platforms that used the FTL switch to B3, we plan to remove LLVM support from the FTL JIT.