On Fri, 7 Apr 2006, Dirk Eddelbuettel wrote:
Hi Brian, On 7 April 2006 at 15:40, Prof Brian Ripley wrote: | Dirk, | | [I didn't get reusable headers from Kurt as he forwarded an attachment.] (Sure, I was just trying to streamline between Bastian, Kurt and myself seemingly emailing at the same time...) | | This was changed based on quite explicit advice in Ulrich Drepper's | DSO paper to use -fpic wherever possible as it can be lot faster. | See http://people.redhat.com/drepper/dsohowto.pdf, e.g. | | `-fpic should be used at all times unless it is absolutely necessary to | use -fPIC'. | | This was part of a concerted effort to close the performance gap between | standalone and shared-library versions of R (and we seem to have about | halved it). Good enough reason for me. | ppc32 is a platform where R can be compiled with -fpic and it does have a | performance advantage. So in principle does m68k, but I last used that in | 1989. (We have been told that the Apple versions of gcc have -fpic = | -fPIC on ppc.) | | I would be very reluctant to change back to -fPIC everywhere, although an | alternative approach would be to make -fPIC the default and use -fpic on | ppc32 and m68k. So what shall we do? I would be happy to try either one of the two approaches you suggest to see what s390 does with it.
Yesterday I added s390* to the list of platforms which need -fPIC in configure. The problem ought to be solved if I did that in all the needed places (which I think I did), so can someone try the current 2.3.0 alpha on s390?
We still need evidence of the various claims about -fpic vs -fPIC on s390. Although I found some evidence of -fPIC being needed in some cases elsewhere (and even more so on s390x than s390), could not even find the GOT size. Bastian claimed
-fpic is documented to have limitations on some systems and is not reliable on some of them for larger software.
Just where *is* this documented for s390, since it is a gcc flag and it is not (I am pretty sure) in the gcc documentation (which I have just been grepping)?
Brian -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
