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tuneinfo2.2 (2010 09)

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tuneinfo2(2) tuneinfo2(2)
NAME
tuneinfo2() - retrieve detailed information about kernel tunable parameters
SYNOPSIS
#include <sys/dyntune.h>
int tuneinfo2(int version,
const char *tunable,
tuneinfo2_t *buf,
size_t *bufsize);
TUNEINFO_STRING(tunable, string)
DESCRIPTION
This function provides detailed information about one or all kernel tunable parameters. If a particular
parameter is of interest, specify it by name in tunable . Otherwise, set tunable to NULL and information
will be returned on all kernel tunable parameters (if the supplied buffer is big enough).
version must always be set to
TUNEINFO_VERSION
.
Information about the selected tunable parameters is returned in
tuneinfo2_t structures and associ-
ated character strings. The buf parameter must specify an address in the caller’s space containing space
for these structures and strings.
bufsize must point to a variable containing the size of the buffer (in bytes).
Since the character strings are of variable length, the caller must first ask how much buffer space is
needed, then allocate the necessary buffer space, and then ask for the tunable information. To calculate
the size of the buffer to hold all the tunables, this function should be called with the parameters buf and
bufsize set to NULL and zero, respectively. The function will return successfully with a return value of 0
and the variable at bufsize will have been changed to contain the amount of space needed to hold all of
the requested data. See the example below.
Each
tuneinfo2_t structure describes a single tunable parameter, and contains at least the following
fields, in unspecified order:
uint64_t ti_name;
Location of the character string containing the name of the tunable.
uint64_t ti_desc;
Location of the character string containing an English description of the parameter.
uint64_t ti_module;
Location of the character string containing name of the DLKM module in which the parameter
is defined. This will be a null string for those parameters defined in the core kernel.
uint64_t ti_current;
The current value of the parameter.
uint64_t ti_bootvalue;
The boot-time value of the parameter.
uint64_t ti_default;
The HP-supplied default value of the parameter.
uint64_t ti_min;
The minimum value of the parameter. Valid only if the TIF_MINVALID flag is set in the
ti_flags word, below.
uint64_t ti_max;
The maximum value of the parameter. Valid only if the TIF_MAXVALID flag is set in the
ti_flags word, below.
Note: The minimum and maximum values returned here are relatively static limits. They
will reflect the limitations of the operating system software, and any limitations placed on this
tunable parameter by the current values of other tunable parameters. However, they do not
reflect any restrictions on the tunable value based on transient factors like the current usage
pattern of the system.
For example, the maximum value returned for
maxuprc (the maximum number of processes a
non-root user may have) will be no greater than the current value of nproc (the maximum
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

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