Java JIT vs. Java AOT vs. Go for Small, Short-Lived Processes

Re:Java JIT vs. Java AOT vs. Go for Small, Short-Lived Proce... by yumaikas on Tuesday December 24, 2019 @10:44AM (#21872717)

A big part of that is that this benchmark is not representative of what general software is like, not in Go, not in Java.

For one thing, most software isn't churning on an array of integers. It's allocating and managing various types of objects.

I haven't written a ton of java, but I suspect that the various reflection-heavy frameworks also impose a lot of overhead into the resulting software that isn't necessarily inherently part of Java the language.

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Re:Java JIT vs. Java AOT vs. Go for Small, Short-Lived Proce... by slaymaker1907 on Tuesday December 24, 2019 @02:00PM (#21874152)

Reflection actually isn’t too inefficient, especially compared to using dynamic languages. I think a lot of the inefficiency is a bunch of small inefficiencies which combine together to make it very heavyweight.

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Re:Java JIT vs. Java AOT vs. Go for Small, Short-Lived Proce... by chrisseaton on Tuesday December 24, 2019 @04:52PM (#21875146)

> Reflection actually isn’t too inefficient

My understanding is that it's completely uncached. It couldn't be any less efficient.

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Re:Java JIT vs. Java AOT vs. Go for Small, Short-Lived Proce... by twic on Wednesday December 25, 2019 @03:23PM (#21880251)

Obtaining a Method object is, I think, pretty slow. But calling through one is fast - I'm not sure what happens exactly, but after some number of calls, some sort of JITting or some such happens and a call via a Method object is as fast as as through a handwritten equivalent (which does the same unpacking of arguments etc).

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Re:Java JIT vs. Java AOT vs. Go for Small, Short-Lived Proce... by kasperni on Tuesday December 24, 2019 @07:19PM (#21875851)

The overhead of, for example, invoking a method via reflection is measured in single-digit nanoseconds. Still not as fast as direct invocation, but unlikely to be a bottleneck unless you perform 10-of-millions of them per second.

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Re:Java JIT vs. Java AOT vs. Go for Small, Short-Lived Proce... by LgWoodenBadger on Tuesday December 24, 2019 @08:00PM (#21876010)

Actually finding the method via reflection is the time consumer.

Once you have the method reference, actually invoking it isn’t any different than a regular method.

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Re:Java JIT vs. Java AOT vs. Go for Small, Short-Lived Proce... by sk5t on Tuesday December 24, 2019 @11:54PM (#21876898)

Although I can't tell you why, it's been my experience that firing a simple method via reflection in both .NET and the JVM is roughly 2x the time of direct calls (or of calls via the 'dynamic' keyword in C#).

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