freebsd stable - Jan 2018 - i386 with 4GB RAM: less than 2GB available on A2SAV (Intel Atom E3940)

I have a lot of machines running with 4 GB physical RAM and, for
some reasons, I still have to use a 32 bits OS.

All of them show something between 3 and 3.5 GB of RAM available
in dmesg but the brand new Supermicro A2SAV really shocked me:

FreeBSD 11.1-STABLE #0: Mon Jan 15 06:57:10 CET 2018
...
real memory  = 4294967296 (4096 MB)
avail memory = 1939558400 (1849 MB)
...

So do people have any ideas how I might get a bit closer to at least
3 GB? I assume there are no FreeBSD knobs which might help but hope
dies last...

28.01.2018 21:57, Andre Albsmeier wrote:
> I have a lot of machines running with 4 GB physical RAM and, for
> some reasons, I still have to use a 32 bits OS.
> 
> All of them show something between 3 and 3.5 GB of RAM available
> in dmesg but the brand new Supermicro A2SAV really shocked me:
> 
> FreeBSD 11.1-STABLE #0: Mon Jan 15 06:57:10 CET 2018
> ...
> real memory  = 4294967296 (4096 MB)
> avail memory = 1939558400 (1849 MB)
> ...
> 
> So do people have any ideas how I might get a bit closer to at least
> 3 GB? I assume there are no FreeBSD knobs which might help but hope
> dies last...
First, try to decrease amount of RAM dedicated to integrated video, if any (BIOS
Setup).

Also, I'd like to know reasons that made you stick to 32 bit OS
as we have pretty good support for 32 bit applications running under 64 bit
system.

On 28 Jan 2018, at 15:57, Andre Albsmeier <Andre.Albsmeier at siemens.com>
wrote:
> I have a lot of machines running with 4 GB physical RAM and, for
> some reasons, I still have to use a 32 bits OS.
> 
> All of them show something between 3 and 3.5 GB of RAM available
> in dmesg but the brand new Supermicro A2SAV really shocked me:
> 
> FreeBSD 11.1-STABLE #0: Mon Jan 15 06:57:10 CET 2018
> ...
> real memory  = 4294967296 (4096 MB)
> avail memory = 1939558400 (1849 MB)
> ...
> 
> So do people have any ideas how I might get a bit closer to at least
> 3 GB? I assume there are no FreeBSD knobs which might help but hope
> dies last...
This is a common problem on i386.  Most likely some ranges are reserved
for I/O mappings, such as video cards.  If you boot with -v, I think the
kernel prints an overview of the physical ram chunks available?  I don't
know of any other way to get such an overview.

Another option is to try PAE, but I have no idea how stable that is...

-Dimitry

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