It was a pretty centralised change to the PassThruAttributeRenderer and PassThruAttributeWriter to support the attributesThatAreSet feature for h: components. And even though effects don't exist for h: components, LocalEffectEncoder was also updated to use the attributesThatAreSet List, for completeness.

Basically, attributesThatAreSet is a List in UIComponent, accessible from UIComponentBase.getAttributes.get("javax.faces.component.UIComponentBase.attributesThatAreSet"), which is a List of all set attributes. This way, we don't have to iterate over all possible pass-through attributes, or effect attributes, for a component, but can instead iterate over the set attributes which are relevant to pass-through or effect rendering. Unfortunately, this feature only exists for stock components, and not third party components, even if they extend stock ones.

Subversion 18311
icefaces\core\src\com\icesoft\faces\context\effects\LocalEffectEncoder.java
icefaces\core\src\com\icesoft\faces\renderkit\dom_html_basic\DomBasicRenderer.java
icefaces\core\src\com\icesoft\faces\renderkit\dom_html_basic\PassThruAttributeRenderer.java
icefaces\core\src\com\icesoft\faces\renderkit\dom_html_basic\PassThruAttributeWriter.java
icefaces\core\src\com\icesoft\faces\webapp\parser\ImplementationUtil.java

Prior to the change, after 500 clicks on the auction monitor the time is:

lifecycle took 12804000 RENDER: 11404000
lifecycle took 12620000 RENDER: 11129000
lifecycle took 13014000 RENDER: 11612000
lifecycle took 12490000 RENDER: 11137000

After the change (revision 18311):

lifecycle took 12985000 RENDER: 11294000
lifecycle took 12593000 RENDER: 11214000
lifecycle took 12526000 RENDER: 11162000
lifecycle took 12728000 RENDER: 11362000

Further investigation is required. I will profile the updated code to see if the optimization is being applied as expected.

Using an h: component variation of the auctionMonitor test:

lifecycle took 10690000 RENDER: 9391000
lifecycle took 10140000 RENDER: 8889000
lifecycle took 9987000 RENDER: 8797000
lifecycle took 10683000 RENDER: 9504000

After the change (revision 18311):

lifecycle took 9686000 RENDER: 8435000
lifecycle took 9514000 RENDER: 8344000
lifecycle took 9629000 RENDER: 8462000
lifecycle took 9473000 RENDER: 8282000

Resulting in a measurable improvement.

On average 7.7% less time for a lifecycle, and 8.4% less time for a render.