> This PR-*draft* is **work in progress** and an invitation to discuss a > possible solution for issue > [JDK-8265891](https://bugs.openjdk.java.net/browse/JDK-8265891). It is *not > yet* intended for a final review. > > As proposed in JDK-8265891, this PR provides an implementation for > `Channels.newInputStream().transferTo()` which provide superior performance > compared to the current implementation. The changes are: > * Prevents transfers through the JVM heap as much as possibly by offloading > to deeper levels via NIO, hence allowing the operating system to optimize the > transfer. > * Using more JRE heap in the fallback case when no NIO is possible (still > only KiBs, hence mostl ynegligible even on SBCs) to better perform on modern > hardware / fast I/O devides. > > Using JMH I have benchmarked both, the original implementation and this > implementation, and (depending on the used hardware and use case) performance > change was approx. doubled performance. So this PoC proofs that it makes > sense to finalize this work and turn it into an actual OpenJDK contribution. > > I encourage everybody to discuss this draft: > * Are there valid arguments for *not* doing this change? > * Is there a *better* way to improve performance of > `Channels.newInputStream().transferTo()`? > * How to go on from here: What is missing to get this ready for an actual > review?
Markus KARG has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision: Draft: Renaming i and separating code into several methods Signed-off-by: Markus Karg <mar...@headcrashing.eu> ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/4263/files - new: https://git.openjdk.java.net/jdk/pull/4263/files/7d18ca62..47ee00a2 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4263&range=02 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4263&range=01-02 Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod Patch: https://git.openjdk.java.net/jdk/pull/4263.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/4263/head:pull/4263 PR: https://git.openjdk.java.net/jdk/pull/4263
