Regarding AIX Memory Utilization usage calculation


 
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Operating Systems AIX Regarding AIX Memory Utilization usage calculation
# 1  
Old 03-11-2013
Regarding AIX Memory Utilization usage calculation

Hello,

Am working on small program that used to calculate the memory usage of AIX servers. Am using svmon -G command to get the memory usage. For example, consider the following output.

Code:
$ svmon -G
               size       inuse        free         pin     virtual   mmode
memory      1957888      670177     1287711      411476      512709     Ded
pg space     131072        2929

               work        pers        clnt       other
pin          350964           0           0       60512
in use       512709           0      157468

PageSize   PoolSize       inuse        pgsp         pin     virtual
s    4 KB         -      269713        2929       85684      112245
m   64 KB         -       25029           0       20362       25029
$

Am using "in use" value at the 6-th line number as memory usage. It gives 26 % as a memory usage. Also am using /bin/ps -eo comm,pmem,args to get the all the process memory usage to confirm with previous calculation.But value calculated by both methods does not match.

Please advise.

Moderator's Comments:
Mod Comment edit by bakunin: my first advice is to use CODE-tags. Its the button misleadingly labeled "CODE" (in case you can't find it).

Last edited by bakunin; 03-12-2013 at 08:16 PM..
# 2  
Old 03-11-2013
Use the
Code:
code

tags for code to preserve spaces.

In a a VM system, grace time and similar VM stats are a better measure of paging activity, which indicates how intensely the free ram pool is used.
# 3  
Old 03-11-2013
Maybe you should also use the "k" option to take account of kernel processes?
Code:
/bin/ps -keo comm,pmem,args

# 4  
Old 03-12-2013
As I posted earlier here - a better "svmon -G" command looks something like this:
Code:
# svmon -G -O unit=auto
Unit: auto
--------------------------------------------------------------------------------------
               size       inuse        free         pin     virtual  available   mmode
memory      512.00M     501.79M       10.2M     246.11M     662.28M      3.49M     Ded
pg space      1.50G     196.83M

               work        pers        clnt       other
pin         219.99M          0K          0K       26.1M
in use      484.54M          0K       17.3M

If you have additional questions about svmon and/or analyzing AIX memory please ask general questions there.

Hope this helps your initial question!
# 5  
Old 03-12-2013
Quote:
Originally Posted by maruthu
Am using "in use" value at the 6-th line number as memory usage. It gives 26 % as a memory usage. Also am using /bin/ps -eo comm,pmem,args to get the all the process memory usage to confirm with previous calculation.But value calculated by both methods does not match.
I noticed the amount of pinned memory. Have you taken shared memory segments into consideration? Use ipcs to analyse these.

I hope this helps.

bakunin
# 6  
Old 03-13-2013
Yes, good old shared memory is used by the traditional UNIX IPCs, including semaphores and queues. I am not sure why these have to be pinned. Pinning is usually for peripheral/I/O support or the paranoid.

You can do similar things without shared memory or pinning using mmap() and files. An area of a file can be mmap()'d by all related processes, no root required. The content is durable through boots, too!
# 7  
Old 03-13-2013
Quote:
Originally Posted by DGPickett
I am not sure why these have to be pinned. Pinning is usually for peripheral/I/O support or the paranoid.
Ahem, "pinned" is not "shared". It is just that most of the standard applications which use pinned memory (foremost Oracle DB) also use shared memory segments to a large extent. Therefore i took an "educated guess" that maybe the presence of pinned memory hints at such a software being used. Why they do it that way? Ask Oracle! I just administrate machines running their product.

I hope this helps.

bakunin
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