On Fri, 24 Feb 2023 19:49:18 GMT, Vicente Romero <vrom...@openjdk.org> wrote:
>>> I think the code should be split a bit using helper methods >> >> OK - will do. >> >>> I'm a bit worried that overuse of streams in this code could imply some >>> performance hit >> >> I asked basically the same question ([in a separate >> thread](https://mail.openjdk.org/pipermail/compiler-dev/2023-February/022259.html)) >> two days ago and nobody replied with a definitive answer (not surprising). >> >> However, note also that in that same thread Christoph reported no timing >> difference between `Stream` vs. `for()` loop >> ([here](https://mail.openjdk.org/pipermail/compiler-dev/2023-February/022261.html)), >> although there were more allocations. FWIW. >> >> Sorry to go off on a tangent here, but I'm sure this issue will come up >> again and it would be nice to have some kind of (informal) policy to go on... >> >> I generally try to follow the "measure first, optimize second" rule to avoid >> preemptive "optimizations" that come at the expense of code clarity for >> unproven meaningful benefit. >> >> So I can de-`Stream` the code but are we sure it's worth it? Are we going to >> have a no `Stream` policy in the compiler code? Why did we develop >> `Stream`'s if they can't be used in a mainstream tool like `javac`? Where >> does the madness end? :) >> >> There is also the larger philosophical question as well, which is that if a >> `Stream` is appreciably slower than the semantically-equivalent `for()` >> loop, then isn't that a Hotspot problem, not a developer problem? > > I'm not saying that we should de-stream the code, actually we can do that > later on, in a separate issue, iff there is a performance related complain, > but it is true that in the past, I have seen some performance issues and the > final culprit have been streams. But you are right it could be that it is not > worthy to affect the readability of the code. OK thanks, I'll leave it for now - but it would be nice to (someday) do some comprehensive testing so we have a better intuitive understanding of the performance impact of using a `Stream` in any particular situation. I wonder if there is some IDE tool that could automatically `Stream`ify and/or de-`Stream`ify loops. If so, we could apply it to the entire compiler and compare... ------------- PR: https://git.openjdk.org/jdk/pull/12645
