JVM 有它的运行时分支预测吗？ 如果是这样，Java 代码中是否有提示分支结果的方法？
[英]Does JVM has its runtime branch prediction? If so, is there a way in Java code to hint branch results?
问题描述
As the title says:
正如标题所说：
I remember that in some C compilers (such as GCC), we're able to give hint to compiler about likely branch prediction results.我记得在某些 C 编译器（例如 GCC）中，我们能够向编译器提示可能的分支预测结果。 Does JVM have such function? JVM有这样的功能吗？
Thank you!谢谢！
3 个解决方案
解决方案1
6 已采纳 2012-07-16 23:47:26
Unless there's some new annotation that's escaped me, no.除非有一些新的注释逃脱了我，否则不会。
On the other hand, it's not clear how terribly useful such a feature would be.另一方面，尚不清楚这样的功能会有多有用。 Remember that, unlike a language such as C/C++, "prediction" at the level of the source code isn't necessarily the best strategy because What The Code Is Actually Doing In Practice as it is running isn't a mystery: the JVM can potentially monitor critical behaviour and if necessary re-compile sections of code in accordance with its measurements.请记住，与 C/C++ 等语言不同，源代码级别的“预测”不一定是最佳策略，因为代码在运行时实际上在做什么并不神秘：JVM可以潜在地监视关键行为，并在必要时根据其测量结果重新编译代码段。
解决方案2
1 2012-07-16 23:47:05
No, the JVM has no such compiler hints or optimizations at the source level.不，JVM 在源代码级别没有这样的编译器提示或优化。
解决方案3
1 2013-09-01 17:11:47
This post is interesting and includes a case where Java branch prediction fails:这篇文章很有趣，包括一个 Java 分支预测失败的案例：
Why is it faster to process a sorted array than an unsorted array? 为什么处理排序数组比处理未排序数组更快？
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