JSF performance?

Any comments on JSF performance? any performance penelty by the extra layer of rendering/processing?

I'd like to share your experience..
Thanks,
-yu

JSF Performance tutorial

http://www.jspolympus.com/JSF/JSFPerformance.jsp

http://www.jamesholmes.com/JavaServerFaces/

More detail
I�m not aware of any performance studies that have been done yet on JSF and made public. I follow this space very closely and keep an extensive set of resources for JavaServerFaces on my website at:

http://www.jamesholmes.com/JavaServerFaces/

There is a project for unit testing JSF called jsftest, but I don�t think there�s any performance stuff out yet. If you come across anything, please share with the group.

-James

Yu,
I don't think the layer of rendering would be significant compared to the time it would take to get data from a database.

I'm more concerned with the number of server round trips. It seems like more is done on the server resulting in more form submissions. Note that I haven't used JSF in a real application yet, only read about it.

Hi Yu,

I think JSF is going to perform as well as the other web frameworks. I think one of the watchouts with JSF is that is extremely powerful and very events driven. Since we are dealing with a stateless protocol each event invoked causes a call back to the server. This means without really understanding JSF it can be very easy to build chatty applications.

Thanks,
John