[Gc] libatomic-ops-7.4.0 not compatible with ppc64le architecture

Lennart Sorensen lsorense at csclub.uwaterloo.ca
Wed Dec 18 13:57:25 PST 2013

On Wed, Dec 18, 2013 at 04:30:54PM +0530, Madhu Pavan wrote:
> Hi Ivan Maidanski,
> We are in the process of adding support for new arch (ppc64le) and
> as part of that we wanted to send patches for config.guess and
> configure as appropriate.
> libatomic-ops-7.4.0 could not be built on ppc64le because it had an
> outdated configure/config.guess/libtool.m4. Since your pkg uses
> libtool and the latest tarball of your pkg didn't build on ppc64le
> due to outdated libtool present on your system. We wanted to request
> you to upgrade your libtool to the alpha release of libtool which
> has all the bits and pieces needed for ppc64le support.
> In that context, I wanted to confirm the below
> 1) Should we send patches to 'gc at linux.hpl.hp.com' mailing list or
> there is some other mailing list ?
> 2) New libtool alpha release which supports ppc64le arch is
> available, you may  pick up the alpha release from either of the
> below :
> ftp://alpha.gnu.org/gnu/libtool/libtool- (1.6MB)
> ftp://alpha.gnu.org/gnu/libtool/libtool- (920KB)
> It would be great if you can install this new libtool which supports
> ppc64le, and spin the pkg and let us know the new tar availability.
> We can test it on ppc64le architecture for you. Please let me know
> if you are planning to release or spin newer version.
> Currently I used
> https://www.hpl.hp.com/research/linux/atomic_ops/download.php4
> Which does not have ppc64le support.
> Your response is highly appreciated.

Well in my experience libatomic-ops doesn't work at all on powerpc,
at least if run on a power7.  The testsuite fails.  It seems to somehow
get by on power6 and older.  Many things have had bugs exposed by power7
since it seems the power7 really relies on the memory model rules of
the power architecture in ways previous designs did not.  Use of memory
barriers have to be done correctly to work on the power7, otherwise
different CPUs will often see different values in memory due to caching.

At least test_stack failed in version 7.2~alpha5+cvs20101124 in Debian
Wheezy when run on an IBM p710 (6 core power7).  Current git tree fails
the same way when built on wheezy.

Len Sorensen

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