From: "kosaki (Motohiro KOSAKI)" <kosaki.motohiro@...>
Date: 2012-06-26T11:47:18+09:00
Subject: [ruby-core:45873] [ruby-trunk - Feature #6615] Release GVL in zlib when calling inflate() or deflate()


Issue #6615 has been updated by kosaki (Motohiro KOSAKI).


Can you please mesure performance impact? Because GVL acquire is costly operation. The performance benefit is not obvious to me.

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Feature #6615: Release GVL in zlib when calling inflate() or deflate()
https://bugs.ruby-lang.org/issues/6615#change-27463

Author: drbrain (Eric Hodel)
Status: Open
Priority: Normal
Assignee: 
Category: ext
Target version: 2.0.0


This patch switches from zstream_run from using rb_thread_schedule() to rb_thread_blocking_region().

I don't see a way to safely interrupt deflate() or inflate() so the unblocking function is empty.

This patch should allow use of output buffer sizes larger than 16KB.  I suspect 16KB was chosen to allow reasonable context-switching time for ruby 1.8 and earlier.  A larger buffer size would reduce GVL contention when processing large streams.

An alternate way to reduce GVL contention would be to move zstream_run's loop outside the GVL, but some manual allocation would be required as currently the loop uses a ruby String as the output buffer.


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