IBM AIX Continuous Availability Features - IBM Redbooks

Note: The frequency of checks made for all checking levels is subject to change.
Example 3-45 Frequencies for xmalloc debug tunable at minimal level
(0)> xm -Q
XMDBG data structure @ 00000000025426F0
Debug State: Enabled
Frequency Base: 00000400
Tunable Frequency
Allocation Record 00000033
Ruin All Data 00000005
Trailer non-fragments 00000005
Trailer in fragments 00000005
Redzone Page 00000005
VMM Check 0000000A
Deferred Free Settings
Fragments 00000005
Non-fragments 00000005
Promotions 00000066
Page Promotion
Frag size Frequency
[00010] 0000000A
[00020] 0000000A
[00040] 0000000A
[00080] 0000000A
[00100] 0000000A
[00200] 0000000A
[00400] 0000000A
[00800] 0000000A
[01000] 0000000A
[02000] 0000000A
[04000] 0000000A
[08000] 0000000A
Ratio of memory to declare a memory leak: 0x400(1024)/0x400(1024)
Outstanding memory allocations to declare a memory leak: -1
Deferred page reclamation count (-1 == when necessary): 16384
Minimum allocation size to force a record for: 1048576
Normal error checking level
When the error checking level is set to normal (level 3), the checks and techniques are
applied at higher frequencies than what minimal checking provides. Normal error checking is
the default level setting in AIX V6.1. It can be set by executing the following command:
errctrl -c alloc.xmdbg errchecknormal
In Example 3-46 on page 128, frequencies for xmalloc tunables at normal level are shown. A
“trailer” will be added to a fragment about 51 (0x33) times out of every 1024 times a fragment
is allocated (about 5%). The deferred free technique will be applied to page promotions about
153 (0x99) times out of every 1024 (0x400) times a fragment is promoted, which is about
15% of the time.
Example 3-46 Frequencies for xmalloc tunables at normal level
(0)> xm -Q
XMDBG data structure @ 00000000025426F0
Debug State: Enabled
128 IBM AIX Continuous Availability Features