Bug 8315

Summary:	Use buffered i/o in ImageStream::getLine() for 10-25% rendering speed improvement
Product:	poppler	Reporter:	Krzysztof Kowalczyk <kkowalczyk>
Component:	general	Assignee:	poppler-bugs <poppler-bugs>
Status:	RESOLVED WONTFIX	QA Contact:
Severity:	normal
Priority:	medium
Version:	unspecified
Hardware:	x86 (IA32)
OS:	Windows (All)
Whiteboard:
i915 platform:		i915 features:
Attachments:	buffered i/o for ImageStream::getLine()

Description Krzysztof Kowalczyk 2006-09-17 17:50:54 UTC

The attached patch makes ImageStream::getLine() use buffered i/o.

For certain kind of images it gives 10-25% speed improvement in rendering page.

It also shows that virtual getChar() is very expensive. Before the change,
FlateStream::getChar() and ImageStream::getLine() were 2 most expensive
functions. After the change, ImageStream::getLine() dropped to position 17 and
FlateStream::readSome() (which replaced FlateStream::getChar()) to position 16.

And if someone is interested in improving the speed of this scenario even
futher, now the most expensive function is Splash::fillImageMask() and 3rd most
expensive is _ftol2_pentium4 (called from Splash::fillImageMask()) so improving
fillImageMask() would give the biggest boost.

Comment 1 Krzysztof Kowalczyk 2006-09-17 17:52:12 UTC

Created attachment 7034 [details] [review]
buffered i/o for ImageStream::getLine()

Comment 2 Krzysztof Kowalczyk 2006-09-17 17:52:35 UTC

BTW: this patch depends on my previous patches to add buffered i/o infrastructure.

Comment 3 Albert Astals Cid 2011-06-19 14:55:30 UTC

Patch does not apply anymore and it seems you are not interested in poppler so i'm closing the bug

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