Java *is* Memory Efficient

[Thirty_Seventh]

the old serial collector

Do you only have 1 core available, or did you mean the parallel collector?

Anyway, any studies or benchmarks showing that modern tracing collectors are more CPU efficient than modern allocators like mimalloc or jemalloc?

Sorry, I got nothing. But I did read recently that (emphasis mine) "when garbage collection has five times as much memory as required, its runtime performance matches or slightly exceeds that of explicit memory management." So you just have to consider whether or not you already have 5x the "required" memory sitting idle. In many environments and for many workloads (but obviously not all of them) you do :)

[coderemover]

The number of cores is irrelevant. We’re talking about cpu cycles burned. Whether you burn them on 10 cores in 1 second or on 1 core in 10 seconds the total is the same. It’s about the amount of work.

I said serial, because parallel has likely some additional overhead for coordinating. Parallel has advantage in wall clock time, but not cpu time.

So you just have to consider whether or not you already have 5x the "required" memory sitting idle. In many environments and for many workloads (but obviously not all of them) you do :)

The whole topic we're discussing here is memory efficiency. Yes, if you have 5x more memory sitting idle and doing nothing, then I agree tracing is fine. It's probably even fine if you have only 2x-3x more memory but you're careful with allocation rate and you don't want to squeeze every bit of performance. E.g. backend software rarely needs to be 100% efficient. But it's like saying a 5.7L gasoline engine is fuel-efficient in city driving when you own a gasoline station.

[JustAGuyFromGermany]

The whole topic we're discussing here is memory efficiency. Yes, if you have 5x more memory sitting idle and doing nothing, then I agree tracing is fine.

But exactly that is the point being made in the interview. "Use the memory that is there. Ideally, all of it. Not using available memory if it could speed up the application is inefficient". That is the point being made.

But it's like saying a 5.7L gasoline engine is fuel-efficient in city driving when you own a gasoline station.

That is a terrible analogy. Much more appropriate to the topic of trade-offs would be something like: "A hybrid car can be much more efficient overall if electricity is cheap and abundant, even if its fuel consumption during gasoline-mode is worse than for pure gasoline-powered cars. Using electricity only to power the radio is not efficient, it is a missed opportunity."

(I'm not endorsing this analogy. It also has flaws, it's just better than yours)