Experiences Getting SystemTap work on OLPC Machine

[Albert Cahalan]

Dan Williams writes:

> You may want to update to the Q2B81 firmware which disables the branch
> prediction workaround, and yields about 25% performance increase when
> using any USB network devices (including the builtin wireless).

Uh, is that safe?

I thought that this was required to avoid causing errors in the
CPU's branch prediction history. Are we now just taking chances?
If USB got fixed to use uncached RAM, what about other devices?