blocks|key|1316774|text|因为使用实时编译时，性能优势微乎其微。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1316775|实际上，许多事情JIT实际上可以更快地完成。|1316776|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Because with Just-In-Time compilation, there is trivial performance benefit. 

Actually, many things JIT can actually do faster.

blocks|key|1101864|text|在运行之后，它已经被JIT编译成Solaris本机代码。如果你在上传到目标站点之前编译它，你不会得到任何其他好处。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1101865|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

It's already will be compiled by JIT into Solaris native code, after run. You can't receive any other benefits if you compile it before uploading at target site.

blocks|key|1316855|text|"Solaris“是操作系统，而不是CPU架构。安装在实际机器上的JVM将编译为本机CPU指令。Solaris可以是SPARC、x86或x86-64体系结构。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1316856|此外，JIT编译器可以根据实际的CPU系列进行特定于处理器的优化。例如，不同的指令序列在Intel+CPU上比在AMD+CPU上更快，针对您的平台的JIT编译器可以利用这些信息来生成高度优化的代码。|1316857|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

"Solaris" is an operating system, not a CPU architecture. The JVM installed on the actual machine will compile to the native CPU instructions. Solaris could be SPARC, x86, or x86-64 architecture.

Also, the JIT compiler can make processor-specific optimisations depending on which actual CPU family you have. For example, different instruction sequences are faster on Intel CPUs than on AMD CPUs, and a JIT compiler for your exact platform can take advantage of this information to produce highly optimised code.

blocks|key|1316885|text|您可能会，也可能不会获得性能优势。但更有可能的是性能损失:静态编译不可能进行即时优化，因此性能只能达到编译器“蒙上眼睛”的程度(而不需要实际分析程序并相应地优化它，而这正是HotSpot等即时编译器所做的)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1316886|直观地说，(资源方面的)编译是多么的便宜，有多少可以通过观察正在运行的程序自动优化，这是非常令人惊讶的。黑魔法，但对我们有好处:-)|1316887|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

You may, or may not get a performance benefit. But more likely you would get a performance penalty: JIT optimization is not possible with static compilation, so the performance would be only as good as the compiler can make it "blindfolded" (without actually profiling the program and optimizing it accordingly, which is what JIT compilers such as HotSpot does).

It's intuitively quite surprising how cheap (resource-wise) compiling is, and how much can be automatically optimized by just observing the running program. Black magic, but good for us :-)

blocks|key|1316905|text|所有这些关于JIT的讨论都已经过时了七年。现在涉及到的技术被称为HotSpot，而不仅仅是JIT。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1316906|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

All this talk of JITs is about seven years out of date BTW. The technology concerned now is called HotSpot and it isn't just a JIT.

blocks|key|1101986|text|我猜是因为JIT+(just+in+time)编译非常先进。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1101987|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I guess because JIT (just in time) compilation is very advanced.

I realize the <a href="https://stackoverflow.com/questions/48144/what-are-advantages-of-bytecode-over-native-code">benefits</a> of bytecode vs. native code (portability). 

But say you always know that your code will run on a x86 architecture, why not then compile for x86 and get the performance benefit? 

Note that I am assuming there is a performance gain to native code compilation. Some folks have answered that there could in fact be no gain which is news to me..

Why isn't more Java software compiled natively?

编译器

Solaris

我意识到字节码与本机代码之间的 (可移植性)。但是如果你总是知道你的代码将在x86架构上运行，为什么不为x86编译并获得性能优势呢？请注意，我假设本机代码编译会有性能提升。有些人回答说，实际上可能没有收益，这对我来说是新的。

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