Robert Collins <[email protected]> writes: > On Fri, 2009-11-20 at 10:00 +0800, jam wrote: >> On Friday 20 November 2009 05:57:09 [email protected] wrote: >> > otherwise, 32bit is better. >> Pray wax lyrical > > Memory footprint. For instance, bzr memory use under 32-bit builds of > python is less than half that of the same workload on 64-bit builds.
db <[email protected]> writes: [... I cited the email to which you are responding, because it is next to impossible to make sense of your comment without that. In general, doing this yourself will help get you answers sooner and more effectively. ...] > on x86_64 is that a python issue or a variable size "issue"? The later: pointers are necessarily 64-bit rather than 32-bit when working with the longer word ISA. Naive software that simply uses the native word size of the machine can also waste memory, since it now allocates 8-byte rather than 4-byte integers. That tends to be more an issue with worse-is-better languages like Perl, Python and Ruby, which don't abstract the platform numeric model at all, because they export the larger words. C is hardly immune, of course... On the other hand, you *also* get a much larger register file, an improve ISA and the ability to assume a much more modern baseline system, so the performance difference for most use is about zero with AMD64 vs i386. Daniel Now, if we used a sane platform this would be different, and we would all be running a 32-bit userspace on a 64-bit kernel anyhow. :) -- ✣ Daniel Pittman ✉ [email protected] ☎ +61 401 155 707 ♽ made with 100 percent post-consumer electrons -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
