Groups paths for cost function calculations
Syntax
group_path [‑name <args>] [‑weight <arg>] [‑default] [‑from <args>]
[‑to <args>] [‑through <args>] [‑quiet] [‑verbose]
Usage
Name | Description |
---|---|
[-name]
|
The name of group, can be multiple names |
[-weight]
|
Cost function Weight, Valid values are 1, 2 Default: 1.0 |
[-default]
|
Restore path to its default group |
[-from]
|
Filter by paths starting at these path startpoints |
[-to]
|
Filter by paths terminating at these path endpoints |
[-through]
|
Consider paths through pins, cells or nets |
[-quiet]
|
Ignore command errors |
[-verbose]
|
Suspend message limits during command execution |
Description
This command lets you group a set of paths for cost function calculations, primarily for timing analysis. The Vivado® tool automatically defines path groups of clock signals for special handling. User-defined path groups can be specified generally as from a startpoint, or to an endpoint, or as specific paths from-through-to specific points. Once a path group has been created, some timing analysis can be performed against it with the report_timing
command.
You can specify a weight for an existing path group of clocks, and let the placement, routing, and optimization engines prioritize those paths first.
To remove a path from a path group, you must specify the -default
option to remove the path from a named path group and restore the path to the standard "default" path group.
This option has the following limitations:
- For paths originally assigned by the tool to a clock path group, the
-default
option will revert those paths to the clock path group instead of reverting them to the "default" path group. -
group_path -default
andreset_path
are completely independent commands. Thereset_path
command doesn't affect path groups, and thegroup_path
command doesn't affect other timing exceptions .
The path groups currently defined in a design can be found by using the get_path_groups
command.
Arguments
-name <arg>
- (Optional) Specifies the name of the path group. If the path group name already exists, the specified paths will be added to the existing group.
-weight [ 1 | 2 ]
- (Optional) Specify the priority of real clock path groups with a value of 1 for standard priority, or 2 for high priority. High priority path groups are processed first during placement, routing, and physical optimization. The default is 1, or standard priority.
-weight
option is only supported for use with clock path groups, and requires the use of -name
to specify the path group. It is not supported for use with user-defined path groups, or with -from/-through/-to
options.
-default
- (Optional) Restores a path group back to the "default" group, which contains all paths not assigned to other group. This option cannot be specified with -name
or -weight
. The path must be specified by -from/-through/-to
as it was initially defined when assigned to a path group.
-from
<args> - (Optional) Include paths starting at the specified startpoints. The startpoints can be specified as pins, ports, or clocks.
-through
<element_names> - (Optional) Include paths routed through the specified pins, cells, or nets.
-to
<path_names> - (Optional) Include all paths to the specified endpoints. Endpoints can be specified as pins, ports, or clocks.
-quiet
- (Optional) Execute the command quietly, returning no messages from the command. The command also returns TCL_OK regardless of any errors encountered during execution.
-verbose
- (Optional) Temporarily override any message limits and return all messages from this command.
set_msg_config
command.Examples
The following example creates a group named signal_grp to the specified registers' endpoints matching *signal*reg/D, and then reports timing on the specified group:
group_path -to [get_pins *signal*reg/D -hierarchical] -name signal_grp
report_timing -group signal_grp
The path group signal_grp is also returned by the get_path_groups
command:
get_path_groups signal_grp
The following example removes the path from the signal_grp, restoring it to the default path group:
group_path -to [get_pins *signal*reg/D -hierarchical] -default