I can't see all of my memory (only 3.5Gb of my 8Gb is seen) in Mandrake 10

jmaxdirect · 04-08-2004, 10:01 PM

Hi, I am a pretty new linux user who is having some trouble, so I hope that someone can help me here. My problem is that I don't thnk my linux kernel recognizes all of my memory.

I built the system myself, and I was told that the more memory and processor you have, thebetter linux will run, so that's what I did. I am using:

Dual Opteron 242 (Tyan 2885 mobo)
8Gb memory (8 x 1Gb 266Mhz)
3Ware 8506-8 SATA Raid Controller
3 x 160Gb Seagate Barracuda drives in Raid 5
GeForce 4 w/128Mb DDR

The installation of Mandrake 10 Community (i586) went fine, and all of my hardware was detected, but when I booted (with default kernel option), and logged into KDE and ran top, only 800Mb (approx) of memory was available.

I tried Redhat for a few months before going to Mandrake, and they had a kernel BigMem that I used (I had only 2Gb of memory before), but I could never get my 2nd processor to be recognized no matter what I did.. and I tried the redhat kernel SMP too, but it didn't work. Anyway, a friend told me to use Mandrake 10 with the 2.6.x kernel, and all of my memory and hardware would be supported, so I did.

When I booted using the Mandrake 10 enterprise kernel, I could see about 3.5Gb of memory.. so that is what I have been using, but I can't tell if both of my processors are supported.. Since my board requires a 2nd processor before the other 4 memory slots become active, I don't know if the processor is being missed or the memory is..

My BIOS can see both processors and all 8Gb of memory, and I installed the latest flash BIOS for my board, and my raid controller, and downloaded all of the Mandrake updates, but I have not been able to find any instructions to make my memory (or 2nd processor) be recognized.

If someone could please help me, either by telling me that I have done something stupid or explain what I did wrong, I would very much appreciate it.

Thanks in advance for your help

fudoki · 04-08-2004, 10:43 PM

You have to use the SMP Kernel with the "High Memory" (not to be confused with windows high memory). It's on the DVD.

fudoki · 04-08-2004, 10:46 PM

Ooops! Just noticed you're running Opterons. You will need to get the SMP kernel FOR Opteron (you'll be GLAD you did). Contact Mandrake. You will probably have to order it from them, or you can join the Mandrake Club and download it, provided you have a high performance internet connection...

Electro · 04-08-2004, 10:55 PM

All you need to do is recompile the kernel for 64 GB memory and for SMP.

What does "cat /proc/cpuinfo" show. If it shows two processors then LINUX found two processors. In "top" you should see ksoftirqd_CPU0 and ksoftirqd_CPU1. Not many programs are program to handle multple threads. If they do, LINUX will balance out the threads to two processors. I think you can tell LINUX to run a program on a desire processor.

Did you test each CPU seperately to make sure each processor works. Also did you check the memory.

For your memory speed, you should have atleast 400 MHz or accessing times of 5 nanoseconds.

jmaxdirect · 04-09-2004, 12:01 AM

fudoki, are you talking about the Mandrake 10 beta1 for AMD64? If so, I downloaded this version, but I had some problems with it.. wasn't too stable, and windows kept crashing.

I will however download the extra CD's for Mandrake (ISO 4, and extra cd's) from the Mandrake club.

Electro, this is my output from the command you suggested:

model name : AMD Opteron(tm) Processor 242
stepping : 1
cpu MHz : 1593.603
cache size : 1024 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 sys
call mmxext lm 3dnowext 3dnow
bogomips : 3129.34

processor : 1
vendor_id : AuthenticAMD
cpu family : 15
model : 5
model name : AMD Opteron(tm) Processor 242
stepping : 1
cpu MHz : 1593.603
cache size : 1024 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 sys call mmxext lm 3dnowext 3dnow
bogomips : 3178.49

It looks like it see's two cpu's (although I don't understand much of the output, it seems to list 2 CPU;s).. so maybe the problem is just with memory config?

Thank you both for helping me

jmaxdirect · 04-09-2004, 12:11 AM

Electro,
Also, here is the output from top..

top - 01:04:37 up 15:43, 0 users, load average: 0.19, 0.11, 0.05
Tasks: 94 total, 1 running, 93 sleeping, 0 stopped, 0 zombie
Cpu(s): 1.0% us, 0.2% sy, 0.0% ni, 98.6% id, 0.2% wa, 0.0% hi, 0.0% si
Mem: 3525692k total, 459536k used, 3066156k free, 71864k buffers
Swap: 8385888k total, 0k used, 8385888k free, 202176k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1703 root 15 0 172m 25m 152m S 3.9 0.7 10:52.44 X
1 root 16 0 1580 516 1424 S 0.0 0.0 0:03.11 init
2 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
3 root 34 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/1
5 root 34 19 0 0 0 S 0.0 0.0 0:00.02 ksoftirqd/1
6 root 5 -10 0 0 0 S 0.0 0.0 0:00.25 events/0
7 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 events/1
8 root 5 -10 0 0 0 S 0.0 0.0 0:00.01 kblockd/0
9 root 5 -10 0 0 0 S 0.0 0.0 0:00.01 kblockd/1
10 root 15 0 0 0 0 S 0.0 0.0 0:00.00 kirqd
11 root 25 0 0 0 0 S 0.0 0.0 0:00.00 pdflush
12 root 15 0 0 0 0 S 0.0 0.0 0:00.01 pdflush
13 root 25 0 0 0 0 S 0.0 0.0 0:00.00 kswapd0
14 root 10 -10 0 0 0 S 0.0 0.0 0:00.00 aio/0
15 root 15 -10 0 0 0 S 0.0 0.0 0:00.00 aio/1
17 root 17 0 0 0 0 S 0.0 0.0 0:00.59 kseriod
21 root 25 0 0 0 0 S 0.0 0.0 0:00.00 scsi_eh_0
25 root 15 0 0 0 0 S 0.0 0.0 0:00.03 kjournald
171 root 17 0 2036 1188 1588 S 0.0 0.0 0:00.25 devfsd
261 root 15 0 0 0 0 S 0.0 0.0 0:00.00 khubd

As for the memory, I looked into 400Mhz, but I couldn't find any ECC DDR memory at that speed... at least not that I could afford right now. I originally ordered 2Gb memory sticks, but they didn't work and I had to exchange them for 1Gb alternative.. I did test several different config's with memory and cpu, and all worked correctly.

Electro · 04-10-2004, 02:14 AM

It looks like LINUX detected your two processors. Now you need to find programs that does multithreading.

Your system will be very limited with your memory. Get atleast four 512 ECC DDR memory that is 400 MHz (5ns) or faster. Also what I found on the internet do not fill all memory banks. You can only put in two memory modules in the memory banks for each processor. Though AMD added a feature to disable the bult-in Northbridge chip, but it seems that chipset desingers are ignoring this feature.

Seagate SATA drives are slow and they can be a pain to setup. Use Western Digital Raptor series of hard drives. They are much, much faster and very easy to setup. RAID 5 or RAID 0 is not very good to store LINUX system files. Use RAID 5 for file storage or using it for video, graphics, sound, web, database.

Trinakria · 04-28-2004, 02:22 AM

Hi everybody,

As jmaxdirect, I have the same pb with memory.

Gentoo running with 2.6.5 on Opteron 246
4x1024MB RAM --> only about 3.5G seen from Linux kernel.

I try to pass the memory amount from bootloader (grub) with mem=4096M but no succes...

Any ideas would be really appreciate,

thx

mattuc · 04-28-2004, 03:23 AM

I'm having a similar prob. I have a 256mb that'll only read as 128.
running RH9.

AutOPSY · 04-28-2004, 03:42 AM

4x1024MB RAM --> only about 3.5G seen from Linux kernel.

I try to pass the memory amount from bootloader (grub) with mem=4096M but no succes...

This is 4 gigs what do you mean no success?

Trinakria · 04-28-2004, 03:52 AM

Dear AutOPSY,

Quote:

This is 4 gigs what do you mean no success?

"no success" because I put 4GB RAM inside

and when i check the memory with "free -m", i obtain

total used free shared buffers cached
3435 392 3043 0 76 165

As you can see more than 500MB are missing....

Trinakria · 04-28-2004, 04:23 PM

Hello everybody,

My mainboard is: Thunder K8W (S2885)

I got new information for my problem: i went to Tyan homepage and check the FAQ related to this mainboard ->

Quote:

Why doesn't all of the memory show up as available when I install more than 4GB?

The BIOS needs to overlay the, APIC, ACPI Table, AGP Aperture, and PCI MMIO (Memory-mapped I/O See PCI Spec 2.3 section 3.2.2 for more information) over the last range of memory under 4GB. Operating System accessible memory and these structures can't both exist at the same place, so this portion of DRAM can't be used and is not reported to the OS. The available memory will decrease when AGP aperture size is increased.

Is there any solution for this?

Not that is readily available. The theoretical possibility exists that the BIOS can map all of the addresses attached to one DIMM module above the 4GB limit, but the BIOS cannot move smaller address ranges piece by piece.

Mapping a whole DIMM is a new concept, unproven in real world testing. It also penalizes 32-bit Operating Systems which cannot use more than 4GB. Since the BIOS doesn't know what OS you have when it does the memory assignments, it has to optimize for the common case -- which is likely a 32-bit OS you may or may not want to use.

In a system with >4GB the BIOS must choose:
(A) Provide as much as possible below 4GB to benefit 32-bit Legacy OS users
(B) Raise one whole DIMM module above the 4GB ceiling to benefit 64-bit OS at the loss of DRAM to a much more memory-limited 32-bit OS.
The current release of the S2885 BIOS chooses option A. We are working on a solution to address option B.

I think i am in big trouble....

If somebody as ideas... ?? my depression would really appreciate

Electro · 04-29-2004, 12:34 AM

I'm sorry about the bad news. Did you try downloading 64-bit linux distributions. You many want to write up a bug report about this issue. Also did you try updating the BIOS.

Trinakria · 04-29-2004, 01:59 AM

Quote:

Originally posted by Electro
I'm sorry about the bad news. Did you try downloading 64-bit linux distributions. You many want to write up a bug report about this issue. Also did you try updating the BIOS.

I am running a Gentoo 64-bit (which by the way works well

(excepted the RAM)

For the bug report i don't know exactly how to proceed and if it is so relevant (it's more a hardware pb ..no? )

The BIOS updating.. i still wait for a response from my "mainboard dealer"

seisman · 04-29-2004, 09:41 AM

I am running a system w/ dual 3.1GHz Xeon processors, 1GB ram, and Nvidia graphics card w/ 512MB ram.

Upon startup, before running any progs, I see that buffer memory is about 97 MB, cached memory is about 154 MB, and free physical memory is about 554 MB.

It seems to me that a LOT of memory is consumed in simply starting up -- doesn't seem right, but maybe RedHat 7.3 is designed to use this much memory.

Any suggestions?