Subj : Re: sync vs. eieio on powerpc
To   : comp.programming.threads
From : Joe Seigh
Date : Mon Feb 28 2005 05:34 pm

On Mon, 28 Feb 2005 22:46:57 +0100, Alexander Terekhov <terekhov@web.de> wrote:

>
> Joe Seigh wrote:
>
> [... eieio ...]
>
> According to various sources, apart from IO space/device memory, eieio
> is nothing but bidirectional "store/store" fence. And, quoting one
> relatively recent IBM paper: "Although eieio orders stores to caching-
> enabled storage, lwsync is the preferred instruction for this purpose.
> It's recommended that eieio not be used for this purpose." Well, IIRC,
> lwsync imposes "load/load", "load/store", and "store/store" ordering.
>

It's not documented in any of the powerpc manuals I have.

http://www-128.ibm.com/developerworks/eserver/articles/powerpc.html

On the G4 lwsync and sync appear to be the same.  It looks like I'll
stick with eieio for the time being.

-- 
Joe Seigh

.