ARM 4.0 Metric Gauges [ARM 4.0 Metrics]

Classes
class	arm4::QArmMetricGauge32
	Implements a 32-bit integer gauge. More...
class	arm4::QArmMetricGauge32Definition
	Marks a metadata binding. More...
class	arm4::QArmMetricGauge64
	Implements a 64-bit integer gauge. More...
class	arm4::QArmMetricGauge64Definition
	Marks a metadata binding. More...
class	arm4::QArmMetricGaugeFloat32
	Implements a 32-bit floating-point gauge. More...
class	arm4::QArmMetricGaugeFloat32Definition
	Marks a metadata binding. More...

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Detailed Description

A gauge value can go up and down, and it can be positive or negative. This is the IETF RFC 1155 definition of a gauge. A gauge should be used instead of a counter when it is not meaningful to sum up the values over an interval. An example is the amount of memory used. If the amount of memory used over 20 transactions in an interval is measured and the average usage for each of these transactions was 15MB, it does not make sense to say that 20*15=300MB of memory were used over the interval. It would make sense to say that the average was 15MB, that the median was 12MB, and that the standard deviation was 8MB. The values can be averaged, maximums and minimums per transaction calculated, and other kinds of statistical calculations performed.

ARM supports three gauge types:

• 32-bit integer: QArmMetricGauge32
• 64-bit integer: QArmMetricGauge64
• 32-bit floating-point: QArmMetricGaugeFloat32 The floating-point standard is IEEE 754 (the same as the Java language).