topic Relevance of expression column in 'kctune' output in Operating System - HP-UX

Relevance of expression column in 'kctune' output

scoolj — Thu, 11 Sep 2008 08:05:17 GMT

Pls refer the below 2 examples. One was set with Dedfault expression, another with an absolute value.

maxdsiz_64bit 4294967296 Default Immed
maxdsiz_64bit 4294967296 4294967296 Immed

man saus...If the tunable value is set to default, then the expression is too set as Default. When the expression is default, the system will choose the tunable value.

I would like to understand the difference between default expression and absolute expression, and how it matter and impact the memory availability on the OS?

Re: Relevance of expression column in 'kctune' output

Sandeep_Chaudhary — Thu, 11 Sep 2008 08:21:39 GMT

suxde033 # kctune|more
Tunable Value Expression Changes
NSTREVENT 50 Default
NSTRPUSH 16 Default
NSTRSCHED 0 Default
STRCTLSZ 1024 Default
STRMSGSZ 0 Default
acctresume 4 Default
acctsuspend 2 Default
aio_listio_max 256 Default Immed
aio_max_ops 2048 Default Immed
aio_monitor_run_sec 30 Default Immed
aio_physmem_pct 10 Default

When a tunable is set to Default, its value is controlled by the HP-UX
kernel, and will be changed whenever the default value for the tunable
is re-computed. (Specific behavior of each tunable is described in
each tunable's man page.) HP recommends that all tunables be set to
Default unless the default value is known to be unsatisfactory.

Setting a tunable to its default value is not the same as setting it
to Default. If the current default value of a tunable example is
4000,

kctune example=4000

will set the tunable's value to 4000 and prevent it from changing when
the default value is re-computed.

kctune example=Default

Re: Relevance of expression column in 'kctune' output

Steven E. Protter — Thu, 11 Sep 2008 08:27:39 GMT

Shalom,

Default in this context as I understand it is the value that the HP-UX installation defaults to. That does not mean it can not be tuned.

In your example there is no impact on the system at all.

The default tag has been removed from the second entry. The amount of memory available is exactly the same.

Nothing really to worry about.

SEP

Re: Relevance of expression column in 'kctune' output

scoolj — Thu, 11 Sep 2008 10:24:41 GMT

Thanks.