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Hi All,

We are facing a strange problem on one of our GS80 server running Tru64 4.0G.

top utility shows actvie memory as 11GB out of total physical memoty 12GB on the
server. We tried to addup memory used by all processes on the server as shown by
ps aux command but it does not add up to 11G. So, can any body suggest why top
shows such a high active memory (& so low Free memory i.e. 200K). Is there any
kernel parameter which causes this behaviour of Tru64 4.0G?
Output from Top Utility as Below:

load averages: 3.29, 3.00,
2.80 08:42:33
209 processes: 3 running, 115 sleeping, 91 idle
CPU states: 24.7% user, 0.0% nice, 11.4% system, 63.7% idle
Memory: Real: 11G/12G act/tot Virtual: 925M/24630M use/tot Free: 200K

PID USERNAME PRI NICE SIZE RES STATE TIME CPU COMMAND
29677 oracle 52 0 844M 598K run 0:46 100.00% oracle
27426 oracle 42 0 844M 802K run 2:54 28.50% oracle
21988 oracle 45 0 844M 1048K sleep 0:01 15.30% oracle
28227 oracle 42 0 844M 1024K sleep 0:00 13.30% oracle
31720 oracle 44 0 844M 745K sleep 0:00 11.40% oracle
2736 oracle 51 0 851M 7651K sleep 0:40 11.00% oracle
24802 oracle 46 0 844M 901K sleep 0:00 10.90% oracle
19289 oracle 44 0 844M 778K sleep 0:00 9.90% oracle
17332 oracle 42 0 844M 811K sleep 0:00 9.70% oracle
26664 oracle 44 0 844M 786K sleep 0:00 9.10% oracle
28245 oracle 44 0 844M 770K sleep 0:00 6.20% oracle
17706 oracle 44 0 844M 860K sleep 0:00 5.60% oracle
22088 oracle 44 0 844M 770K sleep 0:00 5.40% oracle
27460 oracle 44 0 844M 729K sleep 0:01 3.40% oracle
10137 oracle 44 0 844M 688K sleep 0:00 1.90% oracle

Best Regards,
Amr

Hi amr
I'm not sure whether I'm missing the point here, but it makes sense to use all available real memory. If you were to start playing around with tunable parameters in the kernel in an attempt to have more free memory then the swap usage would increase and slow the system down. I would suggest that you have a look at the swap usage and if necessary, and possible increase the physical memory. This would increase the performance of the system.

D'bert

Hi Amr,
According to the source code for top-3.4 the memory information

" /* this is possibly bogus - we work out total # pages by */
/* adding up the free, active, inactive, wired down, and */
/* zero filled. Anyone who knows a better way, TELL ME! */
/* Change: dont use zero filled. */ "

You get a better idea of memory resource usage with vmstat, collect or swapon. By checking the output of these with tops line

Memory: Real: 11G/12G act/tot Virtual: 925M/24630M use/tot Free: 200K

I would say that the 11G is probably "bogus" as it can't be what the source code says it is viz active memory. Either way look at

vmstat -P (active,inactive,wired,ubc,free enries)
(note from V5.1 these will be displayed on a per RAD basis)

swapon -s

and

collect -s m


as dogbert says it makes sense to use most of available memory. You are only using 925M out of 24630M of swap configured so you are not short of swap space. Use ps ax | grep U to look for processes in a U state, this means they are swapped out. On the other hand a process that is swapped out is not using any memory and as long as it doesn't run it is better swapped out than swapped in. It just depends what the processes are.

Regards Tom