Memory Usage from "physmem", "swapinfo", "top", and "glance".
How do I undertand/resolve the different result about the memory usuage from "physmem", "swapinfo", "top", and "glance".
Physical Memory
Can use dmesg to report Physical memory (RAM) info. For example:
# dmesg | grep Phys
Physical: 212992 Kbytes, lockable: 152792 Kbytes, available: 178188 Kbytes
Note:
This system has 2GB physical memory.
Lockable memory is used for
Process images and overhead locked using the plock() system call (see HP-UX Reference entry plock(2)).
Shared memory segments locked with the SHM_LOC command of the shmctl() system call (see HP-UX Reference entry shmctl(2)).
Miscellaneous dynamic kernel data structures used by the shared memory system and some drivers
Can also report Physical memory (RAM) size with adb:
11.x # echo phys_mem_pages/D | adb /stand/vmunix /dev/kmem
physmem:
physmem: 524288
10.x # echo physmem/D |adb -k /stand/vmunix /dev/kmem
physmem:
physmem: 524288
[ TOP ]
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SWAP
# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 288 59 229 20% 0 - 1 /dev/vg00/lvol2
reserve - 146 -146
memory 102 45 57 44%
total 390 250 140 64% - 0 -
The "memory" line in the output of swapinfo is NOT physical memory, rather it is pseudoswap which is calculated to be 75% the size of RAM.
MORE...
[ TOP ]
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top
System: opie1 Sat Dec 18 22:10:07 2004
Load averages: 3.39, 4.42, 4.54
193 processes: 155 sleeping, 38 running
Cpu states:
LOAD USER NICE SYS IDLE BLOCK SWAIT INTR SSYS
3.39 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
Memory: 515216K (441660K) real, 1537516K (1434024K) virtual, 1365132K free
^ ^ ^ ^ ^
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1 2 3 4 5
Memory is not all of physcial, memory, it is:
Total physical memory in the system DEDICATED to text, data or stack segments for all processes on the system.
Total physical memory for runnable processes, as opposed to sleeping processes.
Total memory dedicated to text, data or stack segments for all processes on the system. Some of this is paged out to disk (that is, not all of this is in current physical memory.)
Total memory for runnable processes, as opposed to sleeping or stopped processes.
Physical memory the system considers to be unused and available to new processes. When this value is low, swapping is likely to occur.
For more about top, see top(1) man page. For example:
TTY PID USERNAME PRI NI SIZE RES STATE TIME %WCPU %CPU COMMAND
? 2034 root 154 20 3936K 1084K sleep 1066:16 14.88 14.85 X
? 18768 root 154 30 312K 724K sleep 10:29 6.98 6.97 dtscreen
? 1818 root 152 20 3080K 1460K run 18:29 1.13 1.13 ns-admin
top(1) top(1)
CPU Processor number on which the process is
executing (only on multi-processor
systems).
TTY Terminal interface used by the process.
PID Process ID number.
USERNAME Name of the owner of the process. When the
-u option is specified, the user ID (uid)
is displayed instead of USERNAME.
PRI Current priority of the process.
NI Nice value ranging from -20 to +20.
SIZE Total size of the process in kilobytes.
This includes text, data, and stack.
RES Resident size of the process in kilobytes.
The resident size information is, at best,
an approximate value.
STATE Current state of the process. The various
states are sleep, wait, run, idl, zomb, or
stop.
TIME Number of system and CPU seconds the
process has consumed.
%WCPU Weighted CPU (central processing unit)
percentage.
%CPU Raw CPU percentage. This field is used to
sort the top processes.
COMMAND Name of the command the process is
currently running.
Problems are common to all, but attitude makes the difference
