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> I have no idea if … You have no idea. > He removed LuaJIT LuaJIT supports Lua 5.1 The benchmarks game shows Lua 5.4.7

by igouy 1y ago

hajile 1y ago
> LuaJIT supports Lua 5.1 From what I understand, LuaJIT was removed before Lua 5.2 was released, so that wasn't the reason. https://luajit.org/extensions.html https://luajit.org/extensions.html LuaJIT supports most of the features of Lua versions after 5.1 with the major missing feature being 64-bit integers, but like modern JS JITs, it actually uses 31/32-bit ints internally most of the time. Even in Lua 5.4 code, you are using implicit rather than explicit ints 99% of the time. I haven't run the code to see, but I'm willing to bet that you can copy all the current benchmark code into LuaJIT and it'll run just fine. > You have no idea. I know with certainty that deoptimizations were applied to at least some scripts. Here's three examples for Common Lisp, StandardML, and Haskell over some time. https://zerf.gitlab.io/ComputerLanguageBenchmarksGame2018Archive/alioth.debian.org/tracker/download.php/30402/411005/311777/3309/binary-trees.lisp https://zerf.gitlab.io/ComputerLanguageBenchmarksGame2018Arc... https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe922a0fe1a65ee19c49cb262a1c41319575545/contributed-source-code/shootout/binarytrees/binarytrees.mlton-2.mlton#L9 https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe... https://hackage.haskell.org/package/ajhc-0.8.0.4/src/examples/BinaryTrees.hs https://hackage.haskell.org/package/ajhc-0.8.0.4/src/example... Here's a C example from Mike Pall (presumably the same guy who created LuaJIT) that also got the deopt treatment by Isaac Gouy. https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe922a0fe1a65ee19c49cb262a1c41319575545/contributed-source-code/shootout/partialsums/partialsums.gcc-3.gcc#L5 https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe... It's not a question of if this happens -- only if it affects Lua (I've never checked).
- igouy 1y ago
  > extensions.html On that page, what words do you think support your claim "was removed before Lua 5.2 was released". > I know with certainty I made those code changes. I wrote de-optimized as a joke.
- mardifoufs 1y ago
  Wait, that's news to me. Last time I checked, maybe 2 years ago, luajit supported some Lua >5.2 features. But, just a handful of those. Is it truly supporting most of the newer features nowadays?

> I have no idea if … You have no idea. > He removed LuaJIT LuaJIT supports Lua 5.1 The benchmarks game shows Lua 5.4.7

by igouy 1y ago

> I have no idea if … You have no idea. > He removed LuaJIT LuaJIT supports Lua 5.1 The benchmarks game shows Lua 5.4.7

> LuaJIT supports Lua 5.1 From what I understand, LuaJIT was removed before Lua 5.2 was released, so that wasn't the reason. https://luajit.org/extensions.html https://luajit.org/extensions.html LuaJIT supports most of the features of Lua versions after 5.1 with the major missing feature being 64-bit integers, but like modern JS JITs, it actually uses 31/32-bit ints internally most of the time. Even in Lua 5.4 code, you are using implicit rather than explicit ints 99% of the time. I haven't run the code to see, but I'm willing to bet that you can copy all the current benchmark code into LuaJIT and it'll run just fine. > You have no idea. I know with certainty that deoptimizations were applied to at least some scripts. Here's three examples for Common Lisp, StandardML, and Haskell over some time. https://zerf.gitlab.io/ComputerLanguageBenchmarksGame2018Archive/alioth.debian.org/tracker/download.php/30402/411005/311777/3309/binary-trees.lisp https://zerf.gitlab.io/ComputerLanguageBenchmarksGame2018Arc... https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe922a0fe1a65ee19c49cb262a1c41319575545/contributed-source-code/shootout/binarytrees/binarytrees.mlton-2.mlton#L9 https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe... https://hackage.haskell.org/package/ajhc-0.8.0.4/src/examples/BinaryTrees.hs https://hackage.haskell.org/package/ajhc-0.8.0.4/src/example... Here's a C example from Mike Pall (presumably the same guy who created LuaJIT) that also got the deopt treatment by Isaac Gouy. https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe922a0fe1a65ee19c49cb262a1c41319575545/contributed-source-code/shootout/partialsums/partialsums.gcc-3.gcc#L5 https://github.com/lemire/ComputerLanguageBenchmark/blob/fbe... It's not a question of if this happens -- only if it affects Lua (I've never checked).

igouy 1y ago
> extensions.html On that page, what words do you think support your claim "was removed before Lua 5.2 was released". > I know with certainty I made those code changes. I wrote de-optimized as a joke.
mardifoufs 1y ago
Wait, that's news to me. Last time I checked, maybe 2 years ago, luajit supported some Lua >5.2 features. But, just a handful of those. Is it truly supporting most of the newer features nowadays?