On Sun, 23 Jul 2017 21:22:03 -0700, Rick wrote in message
<20170724042203.GQ7804@???>:

> Quoting Enrico Weigelt, metux IT consult (enrico.weigelt@???):
>
> > Some more: I'm still running 32bit userland even on 64bit machines,
> > to save some memory. Especially for applications that heavily use
> > pointers, it does make a notable difference.
>
> Yes, the fact that x86_64 (and other 64-bit) pointers each chew up 8
> bytes[1] (64 bits) wide, and thereby gobble 2x the RAM, each,
> compared to IA32, can be a significant problem in code that uses
> pointers a great deal, and is very vexing. This irritation's
> inescapable in 64-bit-compiled code, because those pointers need to
> be able to hold the address of any valid memory location the CPU can
> address, whereas 32-bit pointers can reach 4GB address space (which
> seemed impossibly large not so long ago).[2]
>
> So, yes, IA32 compilation (preferably in an otherwise x86_64 host, as
> you're doing) is just the thing for being RAM-thrifty if you don't
> need to access TB of RAM and the code is making heavy use of pointers.
>
> Wikipedia's article on 64-bit computing says:
>
> The main disadvantage of 64-bit architectures is that, relative to
> 32-bit architectures, the same data occupies more space in memory
> (due to longer pointers and possibly other types, and alignment
> padding). This increases the memory requirements of a given process
> and can have implications for efficient processor cache use.
> Maintaining a partial 32-bit model is one way to handle this, and is
> in general reasonably effective.
>
> So, yay for a partial IA32 model within an x86_64 environment:
> smaller pointer-heavy binaries where you need them, but also software
> access to up to 8TB physical RAM (and 4 exabytes = 2^64 of virtual
> memory) where you don't -- best of both worlds.
>
> And, don't forget, year 2038 effects beckon, starting long before
> 2038.
>
>
> [1] There are three distinct data-type models for 64-bit: ILP64,
> LLP64, and LP64. But all have 8-byte pointers. The differences lie
> in lengths of non-pointer data types.
>
> [2] What really changed my mind about this is VM technology. Ability
> to have the production server host in one VM and the beta in another,
> and the small host OS doing security & other monitoring of both, is
> cool. _______________________________________________


..one possible fix: https://wiki.debian.org/X32Port minus systemd


--
..med vennlig hilsen = with Kind Regards from Arnt Karlsen
...with a number of polar bear hunters in his ancestry...
Scenarios always come in sets of three:
best case, worst case, and just in case.