Haifa: Why? Why not?

[Andrew Borthwick]

Hi,

     Could somebody give me a brief pro and con for using the "enable haifa"
option?  I would be using this on a sparc-sun-solaris version 2.5.1.

     In particular, how significant is the speed-up?  Are there any risks?  Can
Haifa be turned on and off dynamically?

Thanks,
Andrew Borthwick