Performance analysis using J2DNBench which was done whilst fixing JDK-7105461
found that very small retangles are slower than X11

The full discussion is here ;
http://mail.openjdk.java.net/pipermail/2d-dev/2012-October/002806.html
Relevant text is
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I used J2DBench with client-jvm on amd64 to test 1x1 rectangles and
didn't find any measureable difference on my notebook (intel + SNA,
fastest driver for 2D as far as I know). Usually even hotspot-client
is quite good optimizing code like this, as the static methods will be
inlined and redundant checks are usually removed.

However, I did find 1x1 fillRect with the xrender pipeline to be a lot
slower compared to X11 which is caused by the xrender pipeline only
having a XRenderFillRectangles native method, which always calls
GetIntArrayCritical on a java array even for a single rectangle.
A fast-path for a single rectangle should pay off for small dimensions.
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