> 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 updated the pull request incrementally with four additional commits since the last revision: - Draft: Test for ChannelInputStream::transferTo - Draft: Using Channels API to invoke sun.nio.ch classes - Draft: MUST check params before ANY other operation - Draft: ChannelInputStream::transferTo Test ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/4263/files - new: https://git.openjdk.java.net/jdk/pull/4263/files/47ee00a2..b431fcd6 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4263&range=03 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4263&range=02-03 Stats: 229 lines in 2 files changed: 229 ins; 0 del; 0 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
