Shulou(Shulou.com)06/02 Report--

This article introduces you how to carry out Cache performance analysis, the content is very detailed, interested friends can refer to, hope to be helpful to you.

Lua5.4-alpha-rc2 has been released for some time, and there is no time to run and see how it performs. I happened to be free recently, so I came to have a look. As a result, the first piece of test code surprised me.

-- a.lua

Collectgarbage ("stop")

Local function foo ()

Local a = 3

For I = 1,64 * 1024 * 1024 do

A = I

End

Print (a)

End

Foo ()

On Lua5.3.4 and Lua5.4-alpha-rc2, the running time of this code is 0.55 and 0.42 seconds.

Through `. / luac-p-l. / lua`, we can see that the performance hotspots in the previous paragraph of the code must be OP_MOVE and OP_FORLOOP. So there must be a change in the execution interpretation code of these two opcode.

I carefully compared the implementation of OP_FORLOOP and OP_MOVE and found that there are three optimizations in the implementation.

1. The execution code of vmcase (OP_FORLOOP) has been removed from'0

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