Re: [PATCH v3 2/6] futex2: Implement vectorized wait

Arnd Bergmann [off-list ref] writes:

On Thu, Sep 16, 2021 at 1:22 PM Peter Zijlstra [off-list ref] wrote:

quoted

On Thu, Sep 16, 2021 at 12:10:25AM -0400, Gabriel Krisman Bertazi wrote:

quoted

I find this weird.  I'm not even juts talking about compat, but even on
native 32-bit. But also, 32 applications on 64, which is a big use
case for games.

Seriously, people still make 32bit applications today? And for legacy
games, I would think the speed increase of modern CPUs would far offset
this little inefficiency.

There are 32-bit Windows games apparently, because it's easier to build it
that way than having both 32-bit and 64-bit versions.

Yes, many modern, recently released, tiple-A Windows games running over
Proton/Wine are published only in 32-bit.  We also keep a 32-bit Proton
for that reason.

There may be native 32-bit games built for Linux from the same sources when
that is not written portably, not sure if that's a thing.

One important reason to use compat mode is for cost savings when you can
ship an embedded system with slightly less RAM by running 32-bit user space
on it. We even still see people running 32-bit kernels on Arm boxes that have
entry-level 64-bit chips, though I hope that those will migrate the
kernel to arm64
even when they ship 32-bit user space.

Similar logic applies to cloud instances or containers. Running a 32-bit
Alpine Linux in a container means you can often go to a lower memory
instance on the host compared to a full 64-bit distro.

        Arnd

-- 
Gabriel Krisman Bertazi