On Tue, 4 May 2021 13:07:34 GMT, Jason Zaugg <jza...@openjdk.org> wrote:
> If the given Path represents a file, use the overload of read defined
> in FileChannel that accepts an explicit position and avoid serializing
> reads.
>
> Note: The underlying NIO implementation is not required to implement
> FileChannel.read(ByteBuffer, long) concurrently; Windows still appears
> to lock, as it returns true for NativeDispatcher.needsPositionLock.
>
>
> On MacOS X, the enclosed benchmark improves from:
>
>
> Benchmark Mode Cnt Score Error Units
> ZipFileSystemBenchmark.read avgt 10 75.311 ? 3.301 ms/op
>
>
> To:
>
>
> Benchmark Mode Cnt Score Error Units
> ZipFileSystemBenchmark.read avgt 10 12.520 ? 0.875 ms/op
src/jdk.zipfs/share/classes/jdk/nio/zipfs/ZipFileSystem.java line 2223:
> 2221: synchronized (zfch) {
> 2222: n = zfch.position(pos).read(bb);
> 2223: }
@LanceAndersen Are you planning to look at this? Do you mind checking the async
close case to make sure that the synchronization isn't masking anything?
Also just to point out that pattern matching for instanceof ca be used here.
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PR: https://git.openjdk.java.net/jdk/pull/3853
