Deep Dive into PHP 8's JIT

Re:Deep Dive into PHP 8's JIT by chubot on Sunday August 30, 2020 @01:33AM (#24321585)

C is frequently 100x faster than Python for code like the example I showed. With autovectorization and other optimizations it can be 500x.

So if a Python JIT does 10-50x better than CPython on a numeric workload, that sounds impressive, but it's still slow compared to C.

And again they don't get 10-50x on string/hash/method call workloads. I think they're lucky to get 2x in some of those cases.

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Re:Deep Dive into PHP 8's JIT by coldtea on Sunday August 30, 2020 @04:35AM (#24322176)

Actually a lot of string stuff is just calling into C, and can be as fast a C (and often is).

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Re:Deep Dive into PHP 8's JIT by jashmatthews on Sunday August 30, 2020 @07:04AM (#24322624)

Just calling into C doesn't give the performance you’re after a lot of the time. The compiler needs to be aware of the properties of strings. Usually they're implemented as either dedicated opcodes or intrinsics. You can see the simple ones in LuaJIT here https://github.com/LuaJIT/LuaJIT/blob/ff1e72acead01df7d8ed0f...

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