Subject: Re: Fork / exec / ctx overhead (on macppc)
To: None <dje@watson.ibm.com>
From: Wolfgang Solfrank <ws@tools.de>
List: port-powerpc
Date: 07/03/2000 18:16:38
Hi,
> I have not performed a thorough examination, but I have mentioned
> to a few developers that the PowerPC interrupt code is flipping the MSR to
> achieve atomic operations instead of using the PowerPC load-linked
> store-conditional instructions. I haven't looked at the memory management
> code to explore how effectively it utilizes the PowerPC MMU.
Hmm, yes, using lwarx/stwcx. may be an option with a potential to improve
performance. Beware that our interrupt/trap handlers don't currently clear
any reservations (at least not the ones I've implemented/looked at). This
is currently done only on process switches. We need to change this if we
want to use lwarx/stwcx.
And yes, there are some inefficiencies in the current PowerPC pmap module.
I'm going to work on this soon.
Ciao,
Wolfgang
--
ws@TooLs.DE Wolfgang Solfrank, TooLs GmbH +49-228-985800