Mike Pall has talked about this in a few places: http://article.gmane.org/gmane.comp.lang.lua.general/58908 http://lambda-the-ultimate.org/node/3851 http://www.reddit.com/user/mikemike As with every performant system, the answer in the end comes down to two things: algorithms and engineering. LuaJIT uses advanced compilation techniques, and it also has a very finely engineered implementation. For example, when the fancy compilation techniques can’t handle a … Read more
This is a known PHP 7.3 bug, which has already been fixed. As a temporary workaround, edit your php.ini file (in my case: vi /usr/local/etc/php/7.3/php.ini), disable PHP PCRE JIT compilation by changing: ;pcre.jit=1 to pcre.jit=0
Doing this by hand needs bravery 😉 Please check this Official MS DebugDiag 2.2: https://www.microsoft.com/en-us/download/details.aspx?id=49924 it has come with analyzer so you don’t have to do with your hand. With DebugDiag, I think you will find your problem faster then ever…
First thing first: With JVM, both interpreter and compiler (the JVM compiler and not the source-code compiler like javac) produce native code (aka Machine language code for the underlying physical CPU like x86) from byte code. What’s the difference then: The difference is in how they generate the native code, how optimized it is as … Read more
I think it may be ASLR at work. You can turn off DEP to test this theory. See here for a C# utility class to check memory information: https://stackoverflow.com/a/8716410/552139 By the way, with this tool, I found that the difference between the maximum and minimum stack size is around 2 KiB, which is half a … Read more
Greater portability: The deliverable (byte-code) stays portable At the same time, more platform-specific: Because the JIT-compilation takes place on the same system that the code runs, it can be very, very fine-tuned for that particular system. If you do ahead-of-time compilation (and still want to ship the same package to everyone), you have to compromise. … Read more
-XX:-TieredCompilation disables intermediate compilation tiers (1, 2, 3), so that a method is either interpreted or compiled at the maximum optimization level (C2). As a side effect TieredCompilation flag also changes the number of compiler threads, the compilation policy and the default code cache size. Note that with TieredCompilation disabled there will be less compiler … Read more
And for the full proof of concept here is a fully capable translation of Rasmus’ approach to JIT into F# open System open System.Runtime.InteropServices type AllocationType = | COMMIT=0x1000u type MemoryProtection = | EXECUTE_READWRITE=0x40u type FreeType = | DECOMMIT = 0x4000u [<DllImport(“kernel32.dll”, SetLastError=true)>] extern IntPtr VirtualAlloc(IntPtr lpAddress, UIntPtr dwSize, AllocationType flAllocationType, MemoryProtection flProtect); [<DllImport(“kernel32.dll”, SetLastError=true)>] … Read more
I’m getting very different results, much less dramatic. But didn’t use the test runner, I pasted the code into a console mode app. The 5% result is ~87% in 32-bit mode, ~100% in 64-bit mode when I try it. Alignment is critical on doubles, the .NET runtime can only promise an alignment of 4 on … Read more
It means exactly what it says on the tin can – it’s measuring the performance of something “small”, like a system call to the kernel of an operating system. The danger is that people may use whatever results they obtain from microbenchmarking to dictate optimizations. And as we all know: We should forget about small … Read more