RFR: JDK-8002152: javadoc could write out files on a worker thread [v2]

[Jonathan Gibbons]

On Mon, 22 Feb 2021 20:55:08 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

> I think we should use suitable tools (e.g. profilers) and/or ask experts in performance. If nothing else, this will help us diagnose such issues in the future.

Yes, but only a little bit yes. I think the "utilization" of minimal/questionable value. The bottom line is a real-time reduction of 10% or more, and, in my opinion, that is enough to declare success.

The latest commit provides more fine-grain control over the number of background threads and queue size, and increasing the number of threads or the queue size actually starts to degrade overall performance, as measured in real time over several runs of building the JDK docs. 

I think there are diminishing returns beyond this point, given that we cannot easily introduce concurrency into the page generation (sigh) because of the underlying javac architecture.

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PR: https://git.openjdk.java.net/jdk/pull/2665