Altera Quartus II Scripting - Manual (Page 557)

Chapter 3: Tcl Packages & Commands 3–427
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© July 2013 Altera Corporation Quartus II Scripting Reference Manual
report_bottleneck
Usage
report_bottleneck [-cmetric <cmetric_name>] [-details] [-metric
<default|tns|num_paths|num_fpaths|num_fanins|num_fanouts>] [-nworst <number>]
[-panel_name <panel_name>] [-stdout] <paths>
Options
-cmetric <cmetric_name>: Custom metric function to evaluate individual nodes
-details: Show the detailed information (number of failing edges, number of fanins,
etc)
-metric <default|tns|num_paths|num_fpaths|num_fanins|num_fanouts>: Indicate the metric
to use to rate individual nodes
-nworst <number>: Specifies the maximum number of nodes to report. If unspecified,
there is no limit
-panel_name <panel_name>: Sends the results to the panel and specifies the name of the
new panel
-stdout: Output the result onto stdout
<paths>: Paths to be analyzed
Description
Reports bottleneck nodes in a design based on user-specified criteria for rating each node.
The following considerations are pre-defined
■ num_fpaths: (default) returns the number of paths that fail timing through the node.
■ num_fanins: returns the number of fanin edges from the node.
■ num_fanouts: returns the number of fanout edges from the node.
■ num_paths: returns the number of paths through the node.
■ tns: returns the total negative slack of all the paths through the node.
The paths to be analyzed can be specified by passing the result of any get_timing_paths call as the last
argument to report_bottleneck. If no paths are specified, report_bottleneck analyzes the worst 1000 setup
paths in the design.
You can also create your own custom criteria for evaluating nodes based on the combination of the
number of fanouts, fanins, failing paths, and total paths.
To use custom criteria, do the following:
1. Create a Tcl procedure that takes one argument, "arg", for example.
2. Use "upvar $arg metric" in the procedure.
3. Calculate the rating based on $metric(tns), $metric(num_fanouts), $metric(num_fanins), and
$metric(num_fpaths).
4. Return the rating with "return $rating".
5. Pass the name of your custom criteria procedure to report_bottleneck using the -cmetric option.
Reports can be directed to the Tcl console (-stdout), the TimeQuest graphical interface (-panel), or a
combination of the two.