Re: i386 with 4GB RAM: less than 2GB available on A2SAV (Intel Atom E3940)

[Andre Albsmeier]

On Sun, 28-Jan-2018 at 10:32:44 -0600, Mike Karels wrote:
> > On 28 Jan 2018, at 15:57, 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.
> > >=20
> > > 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:
> > >=20
> > > FreeBSD 11.1-STABLE #0: Mon Jan 15 06:57:10 CET 2018
> > > ...
> > > real memory  =3D 4294967296 (4096 MB)
> > > avail memory =3D 1939558400 (1849 MB)
> > > ...
> > >=20
> > > 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
> 
> I suspect that the unavailable RAM has been mapped above 4 GB by the BIOS.
> 
> About PAE: at $JOB, we have a FreeBSD 8.2 system that has been running
> PAE reliably since 8.2 was new.  Also, we ship amd64 systems that run
> mostly 32-bit binaries, which works well.

But can the entire userland be 32 bit only?

Maybe I'll try the PAE thing...

-Andre
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Re: i386 with 4GB RAM: less than 2GB available on A2SAV (Intel Atom E3940)

[Andre Albsmeier]

On Sun, 28-Jan-2018 at 17:05:54 +0100, Dimitry Andric wrote:
> On 28 Jan 2018, at 15:57, 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...
> 
> 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

Yes, it does:

real memory  = 4294967296 (4096 MB)
Physical memory chunk(s):
0x1000 - 0x0009afff, 630784 bytes (154 pages)
0x0010 - 0x003f, 3145728 bytes (768 pages)
0x00c28000 - 0x1fff, 524124160 bytes (127960 pages)
0x22151000 - 0x75733fff, 1398681600 bytes (341475 pages)
0x7998e000 - 0x79a5efff, 856064 bytes (209 pages)
0x7a151000 - 0x7a4b, 3600384 bytes (879 pages)
0x7a4eb000 - 0x7aae2fff, 6258688 bytes (1528 pages)
0x7aae5000 - 0x7afe, 5287936 bytes (1291 pages)
avail memory = 1939800064 (1849 MB)

-Andre

> 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
> 



-- 
Win98: useless extension to a minor patch release for 32-bit extensions
   and a graphical shell for a 16-bit patch to an 8-bit operating
   system originally coded for a 4-bit microprocessor, written by
   a 2-bit company that can't stand for 1 bit of competition.
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Re: i386 with 4GB RAM: less than 2GB available on A2SAV (Intel Atom E3940)

[Andre Albsmeier]

On Sun, 28-Jan-2018 at 22:51:04 +0700, Eugene Grosbein wrote:
> 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).

Done that. I have set everything as small as possible but this didn't help.
After a BIOS upgrade, I found the promising option

MAX TOLUD

which was set to 2GB. I changed it to 3GB but nothing changed.

> 
> 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.

I (still) have 32 bit machines and don't want to maintain 2 userlands.
Each machine has its own kernel but userland (updated via nfs) must
remain 32 bit.

Or is it possible to boot a 64 bit kernel and have everything else in
32 bit?
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Re: i386 with 4GB RAM: less than 2GB available on A2SAV (Intel Atom E3940)

[Eric van Gyzen]

On 01/28/2018 10:05, Dimitry Andric wrote:
> On 28 Jan 2018, at 15:57, 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...
> 
> 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.

sysctl machdep.smap on BIOS, machdep.efi_map on UEFI.

Eric
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