Memory Puzzle

[Was_Just19]

I finally moved my main PC to 2010, having tested various things on another PC for the past while.

This PC has a 3.2Ghz P4 with Hyperthreading and 4GB memory.

I am using

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uname -r
2.6.32.11-pclos2.pae
and Top reports

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Mem:   3575656k total,  1511456k used,  2064200k free,    44908k buffers
Hardinfo reports

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Total Memory    3575656 kB
I don't think the total memory shown is appreciably larger than what was available when using a standard kernel.
Should I have even expected it would?

.

[Was_Just19]

I rebooted the machine into the original kernel and here are the results ........

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uname -r
2.6.32.11-pclos2

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top
Mem:   3633084k total,   929528k used,  2703556k free,    38004k buffers

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Hwinfo
Total Memory  3633084 kB

So I am either misreading the whole idea of Total Memory or I have less Total Memory showing when using the pae kernel than the non-pae kernel.

I do understand that there will be some extra overhead when using the pae kernel, but I am addressing total memory in this case, not available memory.

Any comments?

[old_guy]

What I get:
2.6.32.11-pclos2
[earl@localhost ~]$ free
             total       used       free     shared    buffers     cached
Mem:       2854000     442772    2411228          0      20036     196432

Top
Mem:   2854000k total

* * * * * *

2.6.33.2-pclos1.pae
[earl@localhost ~]$ free
             total       used       free     shared    buffers     cached
Mem:       3839152     512860    3326292          0      21064     269380

Top
Mem:   3839152k total

[critter]

Here's mine

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uname -r
2.6.33.2-pclos1.pae

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top
Mem:   4104496k total,   845184k used,  3259312k free,    31836k buffers

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free
             total       used       free     shared    buffers     cached                                     
Mem:       4104496     845580    3258916          0      31928     501884                                     
-/+ buffers/cache:     311768    3792728                                   
hardinfo gives the same total

an earlier pae kernel gave the same results

bfs reports 3373272kb from all commands

have you run a memory test?

[Was_Just19]

have you run a memory test?

No, but it sure looks like I should ........ could it be a BIOS limitation I wonder?

Thanks for the replies guys ......  it seems 'something' is not quite right here ......

[Was_Just19]

I am getting closer to the problem I think ........ 

PCC - Hardware under Memory just lists

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Cache (not specified)
That is the CPU cache and not the RAM!
It appears the RAM is not listed at all!

I ran the PartMagick live CD and checked the memory it recognised ---  4GB RAM

Back to PCLOS and ran lshw to find that the CPU info has this info --

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4GB+ memory addressing (Physical Address Extension),
and the memory shows

slot: System board or motherboard
size: 4GiB

with each memory slot showing

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slot: DIMM_1
size: 1GiB
width: 64 bits
clock: 667MHz (1ns)

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uname -r
2.6.32.11-pclos2.pae

hwinfo ........ System Information ........  only shows

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Total Memory as  3,575,656 kB
htop shows

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412/3491MB
Just to be sure I will need to run a memtest I guess .....  when I figure out how best to do it on this install    .....  a reboot and test it seems.

Will add anything of interest I find   ......

[menotu]

If memory serves me right, some P4 chipsets reserve some memory for hardware devices, thus when you check how much you have in your system it doesn't show the "true" amount.

I think the last Prescott F Core chip (and chipset) was the only one that allowed memory remapping above 4GB for use in 64bit OS's. (Upto 8GB?)

But as I say, this is from "my" memory, which probably needs a good defrag!  

Edit: I use the .pae kernel and my system see's 3969504, whereas the other kernels only see a little over 3GB

[Was_Just19]

menotu, I expected similar results to what you report, which is why I am somewhat puzzled.

I did a memtest and all is well.

I checked the BIOS and it has a setting to limit the OS memory available to 256MB or all of system memory to the OS.

I limited it to 256MB to see what effect it would have on this 2010 KDE install      yeah I know, but I could not reject the opportunity to see 

I am posting this from KDE running in 256MBs

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Mem:    248300k total,   233004k used,    15296k free,     4772k buffers
Swap:  7622792k total,   212488k used,  7410304k free,    55120k cached
well maybe 'running' is a bit optimistic, but it is functioning and for such as launching the browser it is not too bad at all.

The CPU in this is a P4 3.2 Ghz with Hyperhtreading and 64bit extensions and would appear to indicate it is capable of managing 4GB and more of memory.

There is no mention of reserving memory, in the BIOS, other than limiting the OS to 256MBs.
With that option off all the memory is supposed to be available to the OS ...  according to what I read in the BIOS.

I will have another run-through the BIOS when I reboot ans reset the memory settings.

thanks.   

[critter]

Does the motherboard have an on-board graphics card that is stealing some of the ram?

Just a stab in the dark!

[Was_Just19]

Does the motherboard have an on-board graphics card that is stealing some of the ram?

Just a stab in the dark!

Nope   

Thanks for thinking of it. 

[Was_Just19]

I am still trying to find out what is wrong here .......

I should mention a similar thread
http://www.pclinuxos.com/forum/index.php/topic,71234.0.html
which unfortunately is locked so I have no idea what the outcome there was.

A couple of things are the same though

both machines are Dell PCs
the only memory reported is the CPU cache
in my case the pae kernel makes no difference to the situation.

I just installed the kio-sysinfo package to see what it might make of things .......

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Memory Information
Total memory (RAM):  3.4 GB
  Free memory:  2.0 GB (+ 850.4 MB Caches)
  Free swap:  7.3 GB

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OS:  Linux 2.6.32.11-pclos2.pae i686

[BTW .... it seems to have a problem with my network connection too]

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Network Status
Unknown network status


So PCLOS consistently tells me I have less than 4GB of RAM, although the BIOS confirms it is 4GB, as do other utilities such as the PartMagick liveCD.

*******

The only thing I can guess from the info above is that the particular memory controller on the motherboard is not being recognised at all, which would explain why the RAM is not being reported by the OS.

If the OS is not correctly aware of the RAM then I guess what kernel I use is not going to make much difference .....  pae or not.

All suggestions welcome ......


regards.

[critter]

Still a puzzle but have you tried

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cat /proc/meminfo 

That will report anything that the OS can see. If you are still short of 4GB then I would suspect that the BIOS/ Motherboard is cheating on you.

[Was_Just19]

Still a puzzle but have you tried

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cat /proc/meminfo 

That will report anything that the OS can see. If you are still short of 4GB then I would suspect that the BIOS/ Motherboard is cheating on you.

As mentioned above I am told I have 3.4GB RAM, whereas in reality I have 4GB installed, which is recognised by the BIOS and is noted by other means.

PCC - Hardware does not display any RAM at all.

[critter]

PCC hardware aka harddrake takes its info from the /proc system
If PCC reports no ram then perhaps the MB is lying and the OS will never see the correct hardware.
On the bright side
PCLOs needs far less than 4GB - No consolation I know but 

[Was_Just19]

PCC hardware aka harddrake takes its info from the /proc system
If PCC reports no ram then perhaps the MB is lying and the OS will never see the correct hardware.
On the bright side
PCLOs needs far less than 4GB - No consolation I know but 

If the motherboard was lying then how could  lshw  report 4GB, with 1GB in each of four slots?
PartedMagick (or whatever its called) also reports 4GB fitted.

This is more of an annoyance than any great hindrence to getting work completed.

I had intended to use the pae kernel but it seems I am better off using the bfs one.