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. Regards, Dirk | Brian | | On Fri, 7 Apr 2006, Dirk Eddelbuettel wrote: | | > | > [ Let's PLEASE all keep the mail headers in tact. My bad for not including | > Brian earlier, so if possible could all future mails please include Bastian, | > Dirk, Kurt, Brian and the BTS as for this mail ? ] | > | > [ Bastian, I'll send you two emails by Brian. Please consider those before | > replying. We may also want to get Mathias (Debian and Ubuntu gcc maintainer) | > involved. ] | > | > On 7 April 2006 at 13:41, Bastian Blank wrote: | > | On Fri, Apr 07, 2006 at 06:27:25AM -0500, Dirk Eddelbuettel wrote: | > | > I am still a bit suspicious of your | > | > brute force replacement of -fpic. Or do you know for sure that gcc 4.* | > | > requires it? Should it then be conditional on gcc/g++ versions be larger | > | > than a threshold? | > | | > | It is not related to the compiler version. -fpic is documented to have | > | limitations on some systems and is not reliable on some of them for | > | larger software. The usage of -fPIC enables the use of other relocation | > | types which don't have this limitations (or much larger). On most arches | > | it don't make any difference at all. | > | > Bastian, could you please document on which architectures, and for which gcc | > versions, this fails? R actually has a pretty darn good record of building | > on many platforms and gcc variants, as well as a few non gcc compilers, so I | > do not want to discard the accumulated experience from the R side this | > early. | > | > I'm sure we get this resolved in a way that makes everybody happy, and gets R | > to build everywhere. | > | > Thanks, Dirk | > | > | | -- | 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 -- Hell, there are no rules here - we're trying to accomplish something. -- Thomas A. Edison -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
