Memory barriers vs lock/unlock

[Alexander Terekhov]

On 11/8/05, Peter Dimov <pdimov@mmltd.net> wrote:
[...]
> When __exchange_and_add is implemented in terms of __sync_fetch_and_add,
> which seems to guarantee full ordering

I recently gathered that at least some of supposedly fully-fenced IA64
__sync_* intrinsics seem to have mf at the wrong place.

http://www.opengroup.org/austin/mailarchives/ag/msg08717.html
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/nptl/sysdeps/ia64/pthread_spin_unlock.c?rev=1.3&content-type=text/x-cvsweb-markup&cvsroot=glibc
http://www.opengroup.org/austin/mailarchives/ag/msg08740.html

regards,
alexander.