Physical memory problem:less than memory installed

[orickman]

Hello to all,
I am puzzled by the problem:I have a machine rx8640(HP-UX B.11.23 U ia64) with 32G physical memory installed,when I use SAM ,mahinfo,or
dmesg command to check the physical memory size the output is about 28G,less about 4G than the installed physical size.
So where is the else 4G memory?
What about the mechanism if it has?
Thanks for any explaination!
The attachments are instructed by HP may give some additional infomation.

[Peter Godron]

Hi,
and welcome to thre forums !

Your cstm output lists the 32 1Gb memory sticks. So you certainly have 32 Gb.

Could you please run this perl script:
perl -e 'local($PSTAT,$PSTAT_STATIC,$mem_info,$PSTAT_STRUCT)=(239,2,"\0"x120,"LI4L");
syscall($PSTAT,$PSTAT_STATIC,$mem_info,length($mem_info),1,0);
print "RAM=".int((unpack($PSTAT_STRUCT,$mem_info))[4]*((unpack($PSTAT_STRUCT,$mem_info))[5])/(1024*1024))."\n";'

and let us know what the result is.

Please also read:
http://forums1.itrc.hp.com/service/forums/helptips.do?#33 on how to reward any useful answers given to your questions.

[Steven E. Protter]

Shalom,

cstm will likely show a bad memory chip or pair installed. Thats the best way to check it.

SEP

[orickman]

Thanks for consideration!

TO Peter Godron:
The output of the perl script is:
RAM=0
What will I do next?

TO SEP:
"cstm will likely show a bad memory chip or pair installed. Thats the best way to check it."
Any orther detailed instruction? Physical errors in the memory chip or orther parts that resulted in the problem I have posted?

Still confused!

[Andrew Merritt_2]

Hi,
The attachment shows you have 32Gb, both from parstatus and STM, so that looks fine, and none is deallocated.

Can you post the output from machinfo, dmesg, etc. which shows the lower value? Knowing exactly what is being displayed may help diagnose the problem.

Andrew

[orickman]

Any other help?

[Andrew Merritt_2]

Sorry, I don't know the answer, I'd suggest contacting HP support if you don't get any further responses.

To help anyone else, here's the section from the 'machinfo' output attached to the last response:

...
Cache info:
L1 Instruction: size = 16 KB, associativity = 4
L1 Data: size = 16 KB, associativity = 4
L2 Unified: size = 256 KB, associativity = 8
L3 Unified: size = 6144 KB, associativity = 12

Memory = 28670 MB (27.998047 GB)

Firmware info:
Firmware revision = 4.080
FP SWA driver revision: 1.18
IPMI is supported on this system.
BMC version: 1.3
...

Andrew

[orickman]

I appreciate all your fellows' replies very much!I have contacted to HP,they said it was something about "memory interleaving",but how to understand it clearly? Are there any ways to avoid the physical memory "missing"(in fact,it didn't miss) or reduce the "missing size"(may be reduced to 1G or less)?

Thanks!

[Andrew Merritt_2]

Hi, yes, thanks to that pointer I did a bit more digging and memory interleaving is the answer. HP Support were correct, if not as informative as they could have been.

This is new for the latest chipsets, I believe. The Firmware allocates memory to the different partitions based on an algorithm. This works best for powers of 2; it does not seem to cope too well with 3 partitions,and a lot of memory may be unused.

There's a bit about it here, including how to check the values, and how to modify them:
http://docs.hp.com/en/AB297-9003B/ch04s03.html

[Quote:]
HP-UX Support for Cell Local Memory

On servers based on the HP sx2000 chipset, each cell has a cell local memory (CLM) parameter, which determines how firmware interleaves memory residing on the cell.

IMPORTANT: HP-UX 11i Version 2 (B.11.23) supports using CLM. The optimal CLM settings for HP-UX B.11.23 depend on the applications and workload the OS is running.

To check CLM configuration details from an OS, use Partition Manager or the parstatus command. For example, the parstatus -V -c# command and parstatus -V -p# command report the CLM amount requested and CLM amount allocated for the specified cell (-c#, where # is the cell number) or the specified nPartition (-p#, where # is the nPartition number). For details, refer to the HP System Partitions Guide or the Partition Manager Web site (http://docs.hp.com/en/PARMGR2/ ).

To display CLM configuration details from the EFI Shell on a cell-based HP Integrity server, use the info mem command. If the amount of noninterleaved memory reported is less than 512 MB, then no CLM is configured for any cells in the nPartition (and the indicated amount of noninterleaved memory is used by system firmware). If the info mem command reports more than 512 MB of noninterleaved memory, then use Partition Manager or the parstatus command to confirm the CLM configuration details.

To set the CLM configuration, use Partition Manager or the parmodify command. For details, refer to the HP System Partitions Guide or the Partition Manager Web site (http://docs.hp.com/en/PARMGR2/ ).

[End Quote]

Andrew

[orickman]

Many thanks to Andrew for continuing focus on my question!

I have solved the problem instucted by HP Support by using parmodify command to change the configuration for tuning purpose.The command is #parmodify -p 0 -m 0:base:y:ri:4 -m 1:base:y:ri:2 -m.After reboot the checked physical memory size is 32570 MB.