RAM issue!

juanctes · 11-19-2006, 08:01 PM

Hi

i have just bought a 1 Gb PC3200 (400 MHz) RAM and I`m getting mad seeing that the output of free -m is:
22:47:09:~/

Code:

# free -m
             total       used       free     shared    buffers     cached
Mem:           884        122        761          0          9         50
-/+ buffers/cache:         62        821
Swap:          376         35        341
22:57:25:~/
# expr 1024 - 884
140

i know i have 1024!!
My box:
Slack 10.2
custom kernel: (I think that this lines could give a more sharped aye a clue)
# cat .config.Bkp | grep -i mem
CONFIG_SHMEM=y
# CONFIG_TINY_SHMEM is not set
CONFIG_NOHIGHMEM=y
# CONFIG_HIGHMEM4G is not set
# CONFIG_HIGHMEM64G is not set
CONFIG_FLATMEM=y
CONFIG_FLAT_NODE_MEM_MAP=y
# CONFIG_SPARSEMEM_STATIC is not set
# Memory Technology Devices (MTD)
CONFIG_W1_SLAVE_SMEM=m

at startup the bios reports
mem test: 1048576 OK (or something like this, the first 4 digits i recall well)

does any of you know what is happening here?
THANKS!

ilikejam · 11-19-2006, 09:48 PM

Hi.

I'm guessing you've got an integrated video card on your motherboard?

Dave

syg00 · 11-19-2006, 10:12 PM

read this ....

juanctes · 11-20-2006, 12:01 AM

I have just solved it... ALLMOST

i recompiled my kernel with high mem support (4Gb)
and now it recognize 1010 Mb. I dont know why it isnt 1024 but it's enough for me..

THANKS for answearing so fast!

vangelis · 11-20-2006, 01:50 AM

Yes but, I read the link of the friend who posted it above and says

Quote:

Should I enable CONFIG_HIGHMEM for my 1 GB RAM system?

It is advised to not enable CONFIG_HIGHMEM in the kernel to utilize the extra 128 MB you get for your 1 GB RAM system. I/O Devices cannot directly address high memory from PCI space, so bounce buffers have to be used. Plus the virtual memory management and paging costs come with extra mappings. For details on bounce buffers, refer to Mel Gorman's documentation (link below).

Is your system stable? I mean there must be enough users having this issue around the world so your reply on this would be nice. Do some intensive work, maybe load some java apps.

Cheers,

Vangelis

syg00 · 11-20-2006, 06:59 AM

Stability was never the issue - performance was perceived as being the problem.
Read the comments at the bottom of the link I referenced - especially those by Con K. I'm pretty sure his patches have been incorporated into recent 2.6 kernels.

Basically, if you have a 2.6 kernel don't worry about any potential performance hit.

Electro · 11-20-2006, 05:54 PM

I have 1 GB of memory and I do not get any stability problems. I do not get any performance penalty. Actually I get a performance boost and it is noticable in 3D games like Unreal Tournament. I use ECC memory and I recommend using ECC memory. In any OS, higher the memory capacity used, worst the stability. Some people will disagree because in their books non-ECC is just fine.

Software developers that writes software for hardware should pick the best method to handle well in high memory environments. If they do not, you will get performance penalty issues on what you describe.

juanctes · 01-08-2007, 08:29 PM

sorry, was a misstake. deleted the first post.