Hi Shatil, I want to point out that this is not what I am asking for. I specifically did not ask for x32 user-land packages. I am asking for the kernel option that allows x32 binaries to run. I believe this is a very small change. This change allows for x32 containers and chroot environments. Having the kernel configuration for x32 is a necessary step zero to get started at all. How to build the x32 containers is a different problem. One option, for instance, is using the chroot x32 environment available in CernVM. As you can see from the references, we did a number of tests with high-energy physics applications. While the difference in running time is marginal, the difference in memory consumption is always significant: 10%-20%, sometimes even a bit more. I’m not aware of many other tricks that provide such big savings in real-world applications. To summarize, this request is only about the CONFIG_X86_X32 kernel option. Nothing else for the time being. I created a bugzilla record here: https://bugzilla.redhat.com/show_bug.cgi?id=1310158 Cheers, Jakob On 20/02/16 00:58, Shatil Rafiullah wrote: > We configure our own kernel and I've been down the path of configuring > x32 there, but afterwards, getting the user land to play nicely is > another matter. > > Mind you, I was doing this on EL6, and so I needed to introduce a new > glibc that co-existed harmoniously with the upstream one, and then > bootstrap and build GCC with x32 support. Because we were evaluating > software that already existed for x86_64, I patched Yum and RPM to > accept x32 as an additional architecture. > > After all that, I finally ran evaluations on the software we planned > to evaluate in x32, and found the performance gains were negligible > (it was twemcache, which uses tons of pointers, fyi). I highly > recommend doing your own evaluation first, before requesting such a > large change to be applied community-wide. It may not be the panacea > you seek. >