Subj : Re: sync vs. eieio on powerpc
To   : comp.programming.threads
From : Alexander Terekhov
Date : Mon Feb 28 2005 10:46 pm


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.

> And I have no clue why the examples use isync for acquire semantics.

Yeah. I've heard that msync on Power was sorta "revised a bit" a 
couple of years ago. It is still quite brain-dead, I'm afraid.

regards,
alexander.

.