Teledyne LeCroy PETracer EML Analyzer and Exerciser User Manual - Manual (Page 171)

PETracer EML User Manual Chapter 9: Reports and Tools
LeCroy Corporation
163
9.12 Using Unit Metrics
For every protocol unit at the Link or Split transaction level, PETracer™ calculates and
displays a set of metrics. Metrics are measurements of key operating parameters. You
can use metrics to evaluate performance of traffic in the CATC Trace stream.
You can view metrics information in the CATC Trace display, the Traffic Summary
window, and the Bus Utilization window.
PETracer defines different metrics for Link and Split transactions.
Metrics Defined for Link Transactions
Number of Packets: The total number of packets that compose this Link transaction.
Payload: The number of data payload bytes this Link transaction transferred.
Response Time: The time it took to transmit this Link transaction on the PE link, from the
beginning of the first packet in the transaction to the end of the last packet in the
transaction.
Data Throughput: The payload divided by response time, expressed in megabytes per
second.
Note: Usually, the Number of Packets metric for a link transaction is two (in case of
explicit acknowledge) or one (in case of implicit acknowledge). However if
Naks/link level retries are involved, this metric might be higher. As a result,
the Number of Packets metric is useful in highlighting unusual link
transactions.
Metrics Defined for Split Transactions
The following types of metrics currently are defined for Split transactions:
Number of Link Transactions: The total number of Link transactions that compose this
Split transaction.
Payload: The number of payload bytes this Split transaction transferred.
Response Time: The time it took to transmit this Split transaction on the PE link, from
the beginning of the first packet in the Split transaction to the end of the last packet in the
Split transaction;
Data Throughput: The transaction payload divided by response time, expressed in
megabytes per second.
Latency Time: The time measured from the end of the request transaction to the first
completion transmitted in response to the request within this Split transaction.
Note: The Number Of Link Transactions metric for a Split Transaction usually is two
for a Configuration or IO request. It can be bigger then two for a Memory
Read request.