Keysight Technologies U4301, User Manual

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10 Computing and Viewing Decoded Transactions
142 Keysight U4301 PCIe Gen3 Analyzer User’s Guide
3 The third transaction represents the command completion entry that the controller writes to the
completion queue.
4 The fourth transaction represents the MSI-X interrupt generated by the controller to indicate that
a completion entry has been added to the completion queue.
5 The fifth transaction indicates to the controller that the host has processed the completion entry
that the controller added to the completion queue.
Viewing Decoded Payload for NVMe Commands
For NVMe commands that retrieve information from NVMe registers in a specific data structure
format, you can view the returned data structure in the same format as defined in the NVMe protocol
specifications. For instance, the Identify command or the Get Features command returns information
in a specific data structure format defined in NVMe specifications. The Transaction Decode tab
displays the decoded payload for such commands to present the data structure for such commands
as per the defined format.
To view the decoded payload of an NVMe command
1 Right-click the transaction displayed for the command in the Transaction Decode tab.
2 Select
Decode Payload...
The Decode Payload dialog box is displayed with the payload fields matching the fields specified in
NVMe specifications.
The following screen displays the payload details of the NVMe Get Features command. The feature
for which the information is retrieved is LBA Range Type . The displayed payload is as per the data
structure format defined for LBA Range Type in NVMe specifications.
NOTE
You can also visualize a complete set of related transactions (as a super transaction) by
right-clicking the transaction and selecting Visualize Transaction... . See
page 133
for details on
this feature. The following is an example of how the set of transactions for an NVMe Read
command has been sequentially visualized.