In synthetic benchmarks, there was a 40-80% reduction in performance when disabling the JIT. But in a simulated test on YouTube.com, the performance delta was only 6%.
This isn’t the best source as it’s a bit old, and it wasn’t just JIT that was disabled. But the core idea is the same: calculation-heavy code can see an improvement, but most code won’t. Why this matters is how people actually use JS on the web. It’s not for cryptography and such, it’s to manipulate the DOM.
We see a similar pattern: in synthetic benchmarks, the performance gain is large. But Wordpress, by far the largest PHP deployment in the wild, only saw ~3% performance gain. It again comes down to how PHP is used. It’s mostly HTML construction and database calls, neither of which will see any performance gain from a JIT. And, PHP has extensions, where most heavy code is moved to. Things like cryptography are done in PHP extensions, in C, where the JIT doesn’t matter. I’m more familiar with PHP, so I’ve known about the history of PHP not shipping a JIT due to the lackluster performance.
In synthetic benchmarks, there was a 40-80% reduction in performance when disabling the JIT. But in a simulated test on YouTube.com, the performance delta was only 6%.
This isn’t the best source as it’s a bit old, and it wasn’t just JIT that was disabled. But the core idea is the same: calculation-heavy code can see an improvement, but most code won’t. Why this matters is how people actually use JS on the web. It’s not for cryptography and such, it’s to manipulate the DOM.
Microsoft also has some benchmarks here: https://microsoftedge.github.io/edgevr/posts/Super-Duper-Sec...
For PHP the RFC analyzes it: https://wiki.php.net/rfc/jit
We see a similar pattern: in synthetic benchmarks, the performance gain is large. But Wordpress, by far the largest PHP deployment in the wild, only saw ~3% performance gain. It again comes down to how PHP is used. It’s mostly HTML construction and database calls, neither of which will see any performance gain from a JIT. And, PHP has extensions, where most heavy code is moved to. Things like cryptography are done in PHP extensions, in C, where the JIT doesn’t matter. I’m more familiar with PHP, so I’ve known about the history of PHP not shipping a JIT due to the lackluster performance.