On Thu, May 23, 2013 at 11:18 AM, Bill Schmidt <wschm...@linux.vnet.ibm.com> wrote: > On Thu, 2013-05-23 at 08:54 -0600, Sandra Loosemore wrote: >> On 05/23/2013 06:29 AM, Bill Schmidt wrote: >> > >> > Sandra and David, >> > >> > The array-alignment patch is performance-neutral with respect to >> > CPU2006. All variations were in the noise range. >> >> Well, that settles it; I don't see any reason to pursue the patch any >> further if it's not a performance win after all. It probably helped on >> some specific program or benchmark our original customer was interested >> in but that was in an older version of GCC, etc. >> >> Bill, thanks very much for helping with this. > > I'm not sure that's the right message to take away here -- this was just > verifying that we didn't see a benchmarking problem with the patch. It > seems likely that the patch does have benefits; they just aren't exposed > in the particular benchmarks in SPEC CPU2006. > > I think the patch is worth pursuing, since there aren't any negative > consequences in reporting benchmarks.
Sandra, I completely agree with Bill. The intention of the benchmark run was a quick sniff test that the patch did not cause any significant performance degradation, not that the limited set of benchmarks showed improvement. I want to have a version of the patch committed. The only question now is how much of the patch can be committed without exposing potential incompatibilities between different object files. Thanks, David
