[Bug 1898] Optional CPU dependent _Per_CPU_Information attributes

[bugzilla-daemon at rtems.org]

https://www.rtems.org/bugzilla/show_bug.cgi?id=1898

--- Comment #4 from Joel Sherrill <joel.sherrill at oarcorp.com> 2011-08-21 12:36:30 CDT ---
I think I would prefer to broaden this PR a bit.  

We use CPU_STRUCTURE_ALIGNMENT for only one structure -- the priority bit maps.
The Per CPU data is also critical.   

Maybe we should add "CPU_STRUCTURE_SHORT_DATA" to do what you are suggesting.
Or CPU_STRUCTURE_FAST_DATA which is the port's way of answering the question:  

"Generically RTEMS knows it has a very few data structures which if access can
be optimized, then what does the port recommend?"

I can see using both attributes on both pieces of data for speed.  Per CPU
should be aligned and in short data if possible.  The priority bit map access
time impacts the time required for a preemptive thread to block voluntarily.

What do you think?

-- 
Configure bugmail: https://www.rtems.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are watching all bug changes.