OpenTimer shell interprets each command in three forms, builder, action, and accessor.
- a builder command creates lazy tasks to build up a timing analysis framework
- an action command triggers the timing update from the earliest task to the one that produces the result of the action call
- an accessor command dumps static information without altering the internal data structure of the timer
| Command | Form | Description |
|---|---|---|
| read_celllib | builder | reads a liberty format library file |
| read_verilog | builder | reads a gate-level verilog netlist |
| read_spef | builder | reads a file of net parasitics in SPEF |
| read_sdc | builder | reads a Synopsys Design Constraint (sdc) file of version 2.1 |
| read_timing | builder | reads a TAU15 Contest assertion file of timing constraints |
| set_units | builder | specifies the units used to compute timing values and report results |
| set_at | builder | specifies the arrival time of an input port |
| set_rat | builder | specifies the required arrival time of an output port |
| set_slew | builder | specifies the transition time of an input port |
| set_load | builder | specifies the load capacitance of an output port |
| insert_gate | builder | inserts a gate (instance) to the design |
| remove_gate | builder | removes a gate (instance) from the design |
| repower_gate | builder | repowers a gate (instance) with a new cell |
| insert_net | builder | inserts an empty net to the design |
| remove_net | builder | removes a net from the design |
| connect_pin | builder | connects a pin to a net |
| disconnect_pin | builder | disconnects a pin from a net |
| enable_cppr | builder | enables common path pessimism removal analysis |
| disable_cppr | builder | disables common path pessimism removal analysis |
| update_timing | action | updates the timer to keep all timing values up-to-date |
| report_timing | action | reports the critical paths in the design |
| report_at | action | reports the arrival time at a pin |
| report_slew | action | reports the transition time at a pin |
| report_rat | action | reports the required arrival time at a pin |
| report_slack | action | reports the slack at a pin |
| report_tns | action | reports the total negative slack of the design |
| report_wns | action | reports the worst negative slack of the design |
| report_fep | action | reports the total failing endpoints in the design |
| report_area | action | reports the aggregate cell areas of the design |
| report_leakage_power | action | reports the aggregate cell leakage power of the design |
| license | accessor | shows the license information |
| version | accessor | shows the version of the OpenTimer |
| dump_timer | accessor | dumps the design statistics |
| dump_taskflow | accessor | dumps the current lineage graph to a DOT format file |
| dump_graph | accessor | dumps the current timing graph to a DOT format file |
The above list of commands is committed to be stable. Other commands found in shell.hpp but not listed in the table may change in the future release.
The read_celllib command reads a Liberty format library file.
In most cases, this is the first command to initialize a timing analysis framework.
| Argument | Type | Description |
|---|---|---|
| -min | optional | use library for min delay calculation |
| -max | optional | use library for max delay calculation |
| filename | required | the name of the liberty file to read |
By default, OpenTimer use the filename for both min and max delay calculations, if none are given.
The read_verilog command reads a gate-level verilog netlist and initializes the circuit graph
from the given libraries.
| Argument | Type | Description |
|---|---|---|
| filename | required | the name of the gate-level verilog netlist file to read |
The admissible format of verilog files to OpenTimer is described here.
The read_spef command reads a SPEF parasitics file.
| Argument | Type | Description |
|---|---|---|
| filename | required | the name of the SPEF file to read |
The admissible format of SPEF files to OpenTimer is described here.
The read_sdc command reads a Synopsys Design Constraint (SDC) file (version 2.1).
| Argument | Type | Description |
|---|---|---|
| filename | required | the name of the SPEF file to read |
The supporting status of SDC commands is described here.
The read_timing command reads a TAU15 Contest Timing Assertion file
to assert timing constraints.
| Argument | Type | Description |
|---|---|---|
| filename | required | the name of the timing assertion file to read |
The set_units command specifies the units used to compute timing values and
report results.
| Argument | Type | Description |
|---|---|---|
| -time unit | optional | the time unit (s) |
| -capacitance unit | optional | the capacitance unit (F) |
| -resistance unit | optional | the resistance unit (Ohm) |
| -voltage unit | optional | the voltage unit (V) |
| -current unit | optional | the current unit (A) |
| -power unit | optional | the power unit (W) |
The unit consists of a numeric, a scale, and a type.
Each unit is parsed through the following C++ regular expression.
std::regex unit_regex("([\\+-]?\\d*\\.?\\d+)\\s*([fpnumkM]?)\\s*(s)", std::regex::icase);For example, you can use the following:
- set_unit -time 1ps -capacitance -1fF
- set_unit -time 2ns -capacitance -2pF
By default, OpenTimer applies the unit from the file it parsed first (often library unit definitions) and converts the later ones to this basis.
The set_at command specifies the arrival time of an input port at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of the input port pin |
| delay | optional | the arrival time value |
| -min | optional | the minimum arrival time |
| -max | optional | the maximum arrival time |
| -rise | optional | the arrival time at the rising edge |
| -fall | optional | the arrival time at the falling edge |
By default, OpenTimer assumes min split and rise transition. If delay is not given, OpenTimer unsets the arrival time at the pin.
The set_rat command specifies the required arrival time of an output port at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of the input port pin |
| delay | optional | the required arrival time value |
| -min | optional | the minmum required arrival time |
| -max | optional | the maximum required arrival time |
| -rise | optional | the arrival time at the rising edge |
| -fall | optional | the arrival time at the falling edge |
By default, OpenTimer assumes min split and rise transition. If delay is not given, OpenTimer unsets the required arrival time at the pin.
The set_slew command specifies the transition time of an input port at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of the input port pin |
| slew | optional | the input transition time value |
| -min | optional | the minimum transition time |
| -max | optional | the maximum transition time |
| -rise | optional | the transition time at the rising edge |
| -fall | optional | the transition time at the falling edge |
By default, OpenTimer assumes min split and rise transition. If slew is not given, OpenTimer unsets the transition time at the pin.
The set_load command specifies the load capacitance of an output port at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of the input port pin |
| load | optional | the load capacitance value |
| -min | optional | the minimum load capacitance |
| -max | optional | the maximum load capacitance |
| -rise | optional | the load capacitance at the rising edge |
| -fall | optional | the load capacitance at the falling edge |
By default, OpenTimer assumes min split and rise transition. If slew is not given, OpenTimer unsets the transition time at the pin.
The insert_gate command inserts a new gate (instance) upon a cell to the design.
The newly inserted gate is not connected to other gates or nets.
| Argument | Type | Description |
|---|---|---|
| gate_name cell_name | required | the names of the gate and name for the insertion operation |
The remove_gate command removes a gate from the design.
All the connections associated with the gate are removed.
| Argument | Type | Description |
|---|---|---|
| gate_name | required | the name of the gate to remove from the design |
The repower_gate command repowers a gate with another cell.
The new cell must have the same topology as the old cell.
| Argument | Type | Description |
|---|---|---|
| gate_name cell_name | required | the names of the gate and the cell for the repower operation |
The insert_net command inserts an empty net to the design.
| Argument | Type | Description |
|---|---|---|
| name | required | the names of the net to insert into the design |
The remove_net command removes a net from the design.
All components in the net will be disconnected.
| Argument | Type | Description |
|---|---|---|
| name | required | the names of the net to remove from the design |
The connect_pin command connects a pin to a net.
| Argument | Type | Description |
|---|---|---|
| pin_name net_name | required | the names of the pin and the net to enable this connection |
The disconnect_pin command disconnects a pin from the net it is connected to.
| Argument | Type | Description |
|---|---|---|
| pin_name | required | the names of the pin to enable this disconnection |
The enable_cppr command enables the common path pessimism removal analysis.
This triggers path-based timing update and can increase the runtime.
The disable_cppr command disables the common path pessimism removal analysis
and adopts only graph-based analysis.
The update_timing command updates the timer to keep all timing information
(slew, delay, slack) up-to-date.
This is the bottom-most call of every action command.
The report_timing command reports the timing critical paths in the design.
| Argument | Type | Description |
|---|---|---|
| -num_paths k | optional | the number of paths to report |
| -min | optional | the min path |
| -max | optional | the max path |
| -rise | optional | the rising endpoint |
| -fall | optional | the falling endpoint |
If -num_paths k is not given, OpenTimer report the most critical path.
If neither -min nor -max is given, OpenTimer report the critical paths across both splits.
If neither -rise nor -fall is given, OpenTimer report the critical paths across both transitions.
The report_at command reports the arrival time of a pin at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of a pin to query |
| -min | optional | the minimum arrival time |
| -max | optional | the maximum arrival time |
| -rise | optional | the arrival time at the rising edge |
| -fall | optional | the arrival time at the falling edge |
By default, OpenTimer assumes min split and rise transition.
The report_slew command reports the transition time of a pin at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of a pin to query |
| -min | optional | the minimum transition time |
| -max | optional | the maximum transition time |
| -rise | optional | the transition time at the rising edge |
| -fall | optional | the transition time at the falling edge |
By default, OpenTimer assumes min split and rise transition.
The report_rat command reports the required arrival time of a pin at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of a pin to query |
| -min | optional | the minimum required arrival time time |
| -max | optional | the maximum required arrival time time |
| -rise | optional | the required arrival time time at the rising edge |
| -fall | optional | the required arrival time time at the falling edge |
By default, OpenTimer assumes min split and rise transition.
The report_slack command reports the slack of a pin at a given
min/max split and rise/fall transition.
| Argument | Type | Description |
|---|---|---|
| -pin name | required | the name of a pin to query |
| -min | optional | the minimum slack time |
| -max | optional | the maximum slack time |
| -rise | optional | the slack time at the rising edge |
| -fall | optional | the slack time at the falling edge |
By default, OpenTimer assumes min split and rise transition.
The report_tns command reports the total negative slack
(the sum of negative slack across all endpoints)
in the design.
The report_wns command reports the worst negative slack in the design.
The report_fep command reports the total failing endpoints in the design.
The report_area command reports the aggregate cell areas in the design.
The report_leakage_power command reports the aggregate cell leakage power in the design.
The license command shows the license information of OpenTimer.
Currently, OpenTimer is under MIT license and is completely free for use.
The version command shows the version of OpenTimer in the form of major.minor.patch.
The dump_timer command dumps the design statistics.
The output shows a summary of design size, number of pins, number of nets, units, and so on.
The dump_taskflow command dumps the present lineage graph to a DOT format file.
You can use tools like GraphViz to visualize the graph.
The dump_graph command dumps the present timing graph into a DOT format file.
You can use tools like GraphViz to visualize the graph.