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Analyzing PCI Performance
Predefined Performance Measures
Predefined Performance
Measures
For real-time performance measurements, the PCI Analyzer counts
occurrences of predefined events or sequences of events on the PCI bus.
The results are derived and displayed in real time.
Available Measures
The following predefined measures are provided by the PCI Analyzer:
• Throughput
Throughput is the amount of transferred data per time. It is measured
in Mbyte per second. When running a real-time measurement, this
value is displayed in percent of the maximum value (for 33 MHz
systems: 132 Mbyte per second in a 32-bit system, 264 Mbyte per
second in a 64-bit system).
• Utilization
Utilization measures the relation between busy bus time and total bus
time during a transfer.
• Efficiency
Efficiency is a measure of how well the bus is used. It is the most
important value when considering PCI performance.
The efficiency of a transfer is the relation between the amount of data
that was really transferred and the amount of data that could have
been transferred by the used cycles of that transfer (busy clocks).
Efficiency is derived from throughput and utilization. An efficiency
near 100 % means that a device made best use of the time it occupied
the bus (utilization) by transferring as much data as possible during
that time frame (high throughput).
• Retry Rate
This is the ratio between retry transactions and all transactions.
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Agilent E2928A PCI Analyzer User’s Guide, August 2002