Memory Monitoring
Linux Windows AIX Solaris
Linux
To see if your system is short of physical memory, you can use /proc/meminfo
and vmstat:
# more /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 8384733184 3916734464 4467998720 0 43380736 1746464768
Swap: 0 0 0
MemTotal: 8188216 kB
MemFree: 4363280 kB
MemShared: 0 kB
Buffers: 42364 kB
Cached: 1705532 kB
SwapCached: 0 kB
Active: 1730232 kB
ActiveAnon: 1359612 kB
ActiveCache: 370620 kB
Inact_dirty: 1076176 kB
Inact_laundry: 173872 kB
Inact_clean: 177952 kB
Inact_target: 631644 kB
HighTotal: 7455648 kB
HighFree: 4335064 kB
LowTotal: 732568 kB
LowFree: 28216 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Committed_AS: 4099888 kB
HugePages_Total: 0
HugePages_Free: 0
Hugepagesize: 2048 kB |
The 'vmstat' example below shows 3 snapshots of system memory usage
(along with other info) with 1 second apart:
# vmstat 1 3
procs memory swap io system cpu
r b swpd free buff cache si so bi bo in cs us sy wa id
15 0 0 4363300 42364 1705532 0 0 1 0 1 1 0 0 1 0
15 0 0 4363300 42364 1705532 0 0 0 0 117 126 6 94 0 0
15 0 0 4363300 42364 1705532 0 0 0 0 114 112 6 94 0 0
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WindowsWindows Task
Manager can be used to monitor your system. You can start by
"Start->Run->(type) taskmgr and hit <Enter>"
This screen shows a 4-CPU system with current available physical memory = 2.5MB. If
physical memory runs out, your system is paging (disk IO) and your applications will
be slow.
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To automate and capture memory usage into a file using 'perfmon' tool that comes
with Windows 2003, see "perf automation" section from the left navigation.
AIX
'vmstat -s' sends a summary report to STDOUT starting from system
initialization expressed in absolute counts rather than on a interval basis, as
'vmstat 1 10' shows below.
# vmstat -s
725859553 total address trans. faults
2158076 page ins
9763908 page outs
0 paging space page ins
0 paging space page outs
0 total reclaims
325664108 zero filled pages faults
20972 executable filled pages faults
0 pages examined by clock
0 revolutions of the clock hand
0 pages freed by the clock
9798459 backtracks
0 free frame waits
0 extend XPT waits
147220 pending I/O waits
11921921 start I/Os
1700772 iodones
2022681020 cpu context switches
41711252 device interrupts
302225212 software interrupts
8098172091 decrementer interrupts
585603 mpc-sent interrupts
585601 mpc-receive interrupts
0 phantom interrupts
0 traps
6747450643 syscalls
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'vmstat' can be used to determine if there maybe a memory bottleneck
by looking at the 'avm', 'pi' and 'po' columns:
# vmstat 1 10
kthr memory page faults cpu
----- ----------- ------------------------ ------------ -----------
r b avm fre re pi po fr sr cy in sy cs us sy id wa
2 3 298565 163 0 14 58 2047 8594 0 971 217296 1286 23 26 17 34
2 2 298824 124 0 29 20 251 352 0 800 248079 1039 22 28 22 29
1 7 300027 293 0 15 6 206 266 0 1150 91086 479 7 14 9 69
0 13 300233 394 0 1 0 127 180 0 894 6412 276 2 2 0 96
0 14 300453 543 0 4 0 45 82 0 793 5976 258 1 2 0 97
0 14 301488 329 0 2 2 116 179 0 803 6806 282 1 3 0 96
0 14 302207 435 0 5 4 112 159 0 821 12349 402 2 3 0 95
3 9 301740 2240 0 70 9 289 508 0 963 187874 1089 19 31 6 44
1 4 271719 30561 0 39 0 0 0 0 827 203604 1217 21 31 19 30
3 2 269996 30459 0 16 0 0 0 0 764 182351 1387 18 25 34 23
Columns 'pi' and 'po' indicate the number of paging space page-ins/per second and the number
of paging space page-outs/per second. If the values are constantly non-zero, there is most
likely a memory bottleneck. Occasional non-zero values don't necessarily indicate a problem
since paging is the main principal of virtual memory.
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Solaris
'vmstat' can be used to determine if there maybe a memory bottleneck
by looking at the 'avm', 'pi' and 'po' columns:
# vmstat 1 10
kthr memory page faults cpu
----- ----------- ------------------------ ------------ -----------
r b avm fre re pi po fr sr cy in sy cs us sy id wa
1 0 3279604 34633454 0 0 0 0 0 0 7 10513 568 0 0 99 0
0 0 3279573 34633485 0 0 0 0 0 0 6 209 522 0 0 99 0
0 0 3279573 34633485 0 0 0 0 0 0 1 209 520 0 0 99 0
0 0 3279573 34633485 0 0 0 0 0 0 3 222 520 0 0 99 0
0 0 3279573 34633485 0 0 0 0 0 0 1 222 524 0 0 99 0
0 0 3279573 34633485 0 0 0 0 0 0 1 210 516 0 0 99 0
0 0 3279573 34633485 0 0 0 0 0 0 6 209 530 0 0 99 0
Columns 'pi' and 'po' indicate the number of paging space page-ins/per second and the number
of paging space page-outs/per second. If the values are constantly non-zero, there is most
likely a memory bottleneck. Occasional non-zero values don't necessarily indicate a problem
since paging is the main principal of virtual memory.
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