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https://issues.apache.org/jira/browse/TIKA-1007?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14346263#comment-14346263
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Luis Filipe Nassif commented on TIKA-1007:
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I've checked the implementation of PipedReader in openJdk8 b132 and it still
has the same problem: the threads notify each other only when the pipe is full
or empty, so they do not run concurrently.
> Improve Concurrency of ParsingReader
> ------------------------------------
>
> Key: TIKA-1007
> URL: https://issues.apache.org/jira/browse/TIKA-1007
> Project: Tika
> Issue Type: Improvement
> Components: parser
> Affects Versions: 1.2
> Environment: jre 1.7.0_05 x64, Windows 7 Enterprise x64
> Reporter: Luis Filipe Nassif
> Attachments: FastPipedReader.java, FastPipedWriter.java,
> ModifiedParsingReader.java, ModifiedParsingReaderTest.java,
> ParsingReaderTest.java
>
>
> As discussed in TIKA-885, PipedReader and PipedWriter classes have a bug that
> do not allow them to execute concurrently, because they notify each other
> only when the pipe is full or empty, and do not after a char is read or
> written to the pipe. It affects the concurrency of the reader and writer
> sides of ParsingReader. Try to execute the attached ParsingReaderTest.java
> and you will see that only one processor is used (25% CPU on my quad core
> machine). So i modified ParsingReader to use modified versions of PipedReader
> and PipedWriter, that work concurrently. Try to execute the attached
> ModifiedParsingReaderTest.java and you will see that 2 processors are used
> (50% on my machine). The attached FastPipedReader.java and
> FastPipedWriter.java are only for demonstration purposes, because I took the
> base code from the net and changed it, so it could suffer from license
> restrictions.
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