изменить масштаб значения показателя производительности (rescale a performance metric value)
Имя (Name)
pmConvScale - rescale a performance metric value
Синопсис C (C Synopsis)
#include <pcp/pmapi.h>
int pmConvScale(int type, const pmAtomValue *ival,
const pmUnits *iunit, pmAtomValue *oval,
const pmUnits *ounit);
cc ... -lpcp
Описание (Description)
All performance metric values may be encoded in a pmAtomValue
union, defined as follows;
typedef union {
__int32_t l; /* 32-bit signed */
__uint32_t ul; /* 32-bit unsigned */
__int64_t ll; /* 64-bit signed */
__uint64_t ull; /* 64-bit unsigned */
float f; /* 32-bit floating point */
double d; /* 64-bit floating point */
char *cp; /* char ptr */
pmValueBlock *vbp; /* pmValueBlock ptr */
} pmAtomValue;
The encoding of a performance metric's dimensionality and scale
uses a pmUnits structure; see pmLookupDesc(3).
Given a performance metric value pointed to by ival multiply it
by a scale factor and return the value in oval. The scaling
takes place from the units defined by iunit into the units
defined by ounit. Both input and output units must have the same
dimensionality.
The performance metric type for both input and output values is
determined by type, the value for which is typically extracted
from a pmDesc structure, following a call to pmLookupDesc(3) for
a particular performance metric.
pmConvScale is most useful when values returned via pmFetch(3),
(and possibly extracted using pmExtractValue(3)) need to be
normalized into some canonical scale and units for the purposes
of computation.
As a special case, if all components of the dimension are zero,
then this is treated as synonymous with a ``count'' dimension of
one, and so the ``count'' scale components determine the relative
scaling. This accommodates the case where performance metrics
are dimensionless, without special case handling on the part of
the caller.
Диагностика (Diagnostic)
PM_ERR_CONV
iunit and ounit have different dimensionality, or have
inappropriate type
PM_ERR_UNIT
Inappropriate iunit or ounit parameter
Смотри также (See also)
PMAPI(3), pmAtomStr(3), pmExtractValue(3), pmFetch(3),
pmLookupDesc(3), pmPrintValue(3), pmTypeStr(3) and pmUnitsStr(3).
