Discussing address space for 32bit apps

[Andrew Eikum]

On Mon, Nov 12, 2018 at 02:45:34PM +0330, Henri Verbeet wrote:
> On Sun, 11 Nov 2018 at 14:53, Axel Davy <davyaxel0 at gmail.com> wrote:
> > A tester who doesn't use pulseaudio said he didn't run into issues with
> > Mass Effect 1. Indeed the fact pulseaudio takes almost half the space
> > allocated by all the linux libs, which could explain that.
> >
> The short version is "Yes, it's hard, and don't use PulseAudio."
> 
> There's ultimately not a lot we can do about this, other than being
> careful about our own address space usage, and trying to convince
> libraries we depend on to do the same. PulseAudio is one offender, but
> e.g. LLVM isn't great for address space usage either. If it's any
> consolation, the situation is much worse on MacOS than on Linux.
> 

I find using a system with PulseAudio much more pleasant than one
without.

It is annoying that it takes up so much memory by default.  Each PA
stream that we open reserves 64 MiB of RAM, which can add up quickly
depending on how the game does its audio.  You can fix that by
changing the value of shm-size-bytes in /etc/pulse/daemon.conf to
something more reasonable, like 1 MiB:

    shm-size-bytes=1048576

I'm not totally sure what the impact of this change is. My guess is it
will limit the maximum latency for PA clients, which may increase CPU
usage a tiny amount for non-time-critical streams. I don't know if
upstream PA would be interested in changing the default. I don't think
I ever asked.

Andrew