[I'm attaching Richard's original mail since it was only sent to opensolaris-arc and probably didn't get into the case mail log]
Richard L. Hamilton wrote: > I can think of three main categories of capacity limits on 32-bit that might > be higher on 64-bit: > * file size max of 2GB > * register size and usage > * available address space, and therefore amount that can be mmap()'d at once > (Also, IIRC stdio is supposed to handle > 256 file pointers on 64-bit.) > > AFAIK, only where the address space is an issue is 64-bit all that beneficial > on SPARC. > ... > The file size limit can be lifted on 32-bit with large file support > (lfcompile(5)). > The register usage can be altered in an often helpful way by compiling with > -xarch=v8plus. Even the stdio problem could be circumvented (using AT&T > SFIO in place of libc stdio), although that may be an architectural no-no for > now. Roland: Could you respond to Richards comments - it may be that by using large file support you could get the behavior you want - on both x86 and SPARC. > IMO, a better statement might be that if something is being touched, the > compilation options including 32 vs 64-bit, and the other measures for 32-bit, > should be re-examined to increase capacity limits without performance > regression or breaking compatibility (i.e. public libs that have been > available > in 32-bit should continue to be, and if not already both 32-bit and 64-bit, > usually should be) with any supported platform. This seems to be a reasonable "design/implementation policy" that could replace the defacto "do it all or do nothing" and "you can't do it anyways" ones. Garrett D'Amore wrote: > Bart Smaalders wrote: >> My question here is whether there is a plan about what to do w/ 32bit >> only (x86) systems in regards to whatever limit this change avoids.... > > I think the above question (the behavioral difference) is one that > really needs to be addressed. It may be that the answer is that we > don't care about the limit on 32-bit only systems, but what are we going > to do for 64-bit-capable x86 boxes? Build and deliver 64-bit binaries? Maybe even as a followup to this project? With a 32-bit system, you may just be stuck with 32 bit limits. Tough. With a 64-bit system, you shouldn't be stuck with a 32-bit limit just because someone might have a 32 bit system that behaves differently. Isn't that why we developed 64 bit systems in the first place? Isn't that why we are doing the OpenSolaris thing - to find and fix these kinds of problems? -John -------------- next part -------------- An embedded message was scrubbed... From: "Richard L. Hamilton" <[email protected]> Subject: Re: Switch SPARC GNU coreutils+bash from 32 to 64bit [PSARC/2008/351 Date: Sat, 31 May 2008 06:59:51 -0700 (PDT) Size: 7950 URL: <http://mail.opensolaris.org/pipermail/opensolaris-arc/attachments/20080602/0a4dbb4f/attachment.nws>
