memory

[j773303]

How to know the Physical memory and free memory?
What's mean of the
Memory 106276k(12544k) real, 247324k(12284k) virtual, 1708956k free ? what's the real, virtual free??
And in dmesg, can view the available: 1906408Kbytes, what's the mean of the available? why it is different with free of TOP?

[twang]

to know current physical memory setting, check /var/adm/syslog/syslog.log, or you may use dmesg or
adb command:
use dmesg command,
example:
#dmesg
:

use adb command,
O for HP-UX 10.X
#echo physmem/D | adb /stand/vmunix /dev/kmem


O for HP-UX 11.X systems running on 32 bit architecture:
#echo phys_mem_pages/D | adb /stand/vmunix /dev/kmem


O for HP-UX 11.X systems running on 64 bit architecture:
#echo phys_mem_pages/D | adb64 /stand/vmunix /dev/mem


for virtual memory size, you may use swapinfo
#swapinfo -am

[Bill Douglass]

Top is showing you the amount of real and virtual memory being used. The amount in parenthesis is the "active" amount of real or virtual memory in use, that is, belonging to recently run processes.

dmesg displays the total system RAM available, after the kernel has loaded.

[j773303]

The real memory and virtail memory size is controlled by OS? Is it possibly modify it?

[T G Manikandan]

dmesg shows the amount of memory on the system

Physical--Total memory on the system.

lockable_memory-->pages in memory for the lifetime of a process is lockable memory.

Available memory--->Total memory minus the memory allocated for the kernel.

Available memory can be increased/decreased with several factors,one being the kernel parameters.

More values for the kernel parameters brings down the value of available memory on the system.

Virtual memory is the swap space.

Regarding the top memory value description this doc can help u

http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000056883261

Revert on any clarification.

check the /usr/share/doc/mem_mgt.txt to know about the memory management on the hpux system.

[Frank Slootweg]

Basically, you should use the right tool for the right job.

top(1) is mainly intended to show *CPU*, not memory, usage information. As you have found the memory information displayed by top(1) is very confusing for most people. It is best to ignore it.

twang and T.G. Manikandan have given methods to display the amount of physical memory (RAM) in your system.

To see the amount of free memory, use vmstat(1), for example "vmstat 1 1" and look at the "free" column. That shows the amount of free memory in pages, where a page is 4KBytes.

Do not worry if you see 'little' free memory. HP-UX uses main (RAM) memory as a cache. A good cache is always full. In order to be able to quickly start new small processes, HP-UX keeps memory nearly full, where "nearly" is upto some 95 percent.

A better tool (than top, sar, vmstat and iostat) is the optional product Glance. There is a trial version on your Application media.