Detailed Routing

Detailed Routing #

The Detailed Routing (drt) module in OpenROAD is based on the open-sourcedetailed router, TritonRoute. TritonRoute consists of several mainbuilding blocks, including pin access analysis, track assignment,initial detailed routing, search and repair, and a DRC engine.The initial development of therouteris inspired by theISPD-2018 initial detailed routingcontest. However, the current frameworkdiffers and is built from scratch, aiming for an industrial-oriented scalableand flexible flow.

TritonRoute provides industry-standard LEF/DEF interface withsupport ofISPD-2018 andISPD-2019 contest-compatible routeguide format.

Commands#

Note

Parameters in square brackets[-paramparam] are optional.
Parameters without square brackets-param2param2 are required.

Detailed Route#

This command performs detailed routing.

Developer arguments

-or_seed,-or_k

Distributed arguments

-distributed ,-remote_host,-remote_port,-shared_volume,-cloud_size

Pin Access arguments

-via_in_pin_bottom_layer,-via_in_pin_top_layer,-via_access_layer,-min_access_points

detailed_route[-output_mazefilename][-output_drcfilename][-output_cmapfilename][-output_guide_coveragefilename][-drc_report_iter_stepstep][-db_process_nodename][-disable_via_gen][-droute_end_iteriter][-via_in_pin_bottom_layerlayer][-via_in_pin_top_layerlayer][-via_access_layerlayer][-or_seedseed][-or_kk][-bottom_routing_layerlayer][-top_routing_layerlayer][-verboselevel][-distributed][-remote_hostrhost][-remote_portrport][-shared_volumevol][-cloud_sizesz][-clean_patches][-no_pin_access][-min_access_pointscount][-save_guide_updates][-repair_pdn_viaslayer][-single_step_dr]

Options#

Switch Name	Description
`-output_maze`	Path to output maze log file (e.g.`output_maze.log`).
`-output_drc`	Path to output DRC report file (e.g.`output_drc.rpt`).
`-output_cmap`	Path to output congestion map file (e.g.`output.cmap`).
`-output_guide_coverage`	Path to output guide coverage file (e.g.`sample_coverage.csv`).
`-drc_report_iter_step`	Report DRC on each iteration which is a multiple of this step. The default value is`0`, and the allowed values are integers`[0,MAX_INT]`.
`-db_process_node`	Specify the process node.
`-disable_via_gen`	Option to diable via generation with bottom and top routing layer. The default value is disabled.
`-droute_end_iter`	Number of detailed routing iterations. The default value is`-1`, and the allowed values are integers`[1,64]`.
`-via_in_pin_bottom_layer`	Refer to pin access argumentshere.
`-via_in_pin_top_layer`	Refer to pin access argumentshere.
`-via_access_layer`	Refer to pin access argumentshere.
`-min_access_points`	Refer to pin access argumentshere.
`-or_seed`	Refer to developer argumentshere.
`-or_k`	Refer to developer argumentshere.
`-bottom_routing_layer`	Deprecated. Use the`set_routing_layers` command instead.
`-top_routing_layer`	Deprecated. Use the`set_routing_layers` command instead.
`-verbose`	Sets verbose mode if the value is greater than 1, else non-verbose mode (must be integer, or error will be triggered.)
`-distributed`	Refer to distributed argumentshere.
`-remote_host`	Refer to distributed argumentshere.
`-remote_port`	Refer to distributed argumentshere.
`-shared_volume`	Refer to distributed argumentshere.
`-cloud_size`	Refer to distributed argumentshere.
`-clean_patches`	Clean unneeded patches during detailed routing.
`-no_pin_access`	Disables pin access for routing.
`-save_guide_updates`	Flag to save guides updates.
`-repair_pdn_vias`	This option is used for PDKs where M1 and M2 power rails run in parallel.

Developer arguments#

Some arguments that are helpful for developers are listed here.

Switch Name	Description
`-or_seed`	Random seed for the order of nets to reroute. The default value is`-1`, and the allowed values are integers`[0,MAX_INT]`.
`-or_k`	Number of swaps is given by\(k * sizeof(rerouteNets)\). The default value is`0`, and the allowed values are integers`[0,MAX_INT]`.

Detailed Route Debugging#

The following command and arguments are useful when debugging errormessages fromdrt and to understand its behavior.

detailed_route_debug[-pa][-ta][-dr][-maze][-netname][-pinname][-boxx1y1x2y2][-iteriter][-pa_markers][-dump_dr][-dump_dirdir][-snapshot_dirdir][-dump_last_worker][-pa_edge][-pa_commit][-write_net_tracks]

Options#

Switch Name	Description
`-pa`	Enable debug for pin access.
`-ta`	Enable debug for track assignment.
`-dr`	Enable debug for detailed routing.
`-maze`	Enable debug for maze routing.
`-net`	Enable debug for net name.
`-pin`	Enable debug for pin name.
`-box`	Set the box for debugging given by lower left/upper right coordinates.
`-worker`	Debugs routes that pass through the point`{x,y}`.
`-iter`	Specifies the number of debug iterations. The default value is`0`, and the accepted values are integers`[0,MAX_INT`.
`-pa_markers`	Enable pin access markers.
`-dump_dr`	Filename for detailed routing dump.
`-dump_dir`	Directory for detailed routing dump.
`-snapshot_dir`	Directory for snapshots produced if the debug level of`DRTsnapshot` is set to 1.
`-pa_edge`	Enable visibility of pin access edges.
`-pa_commit`	Enable visibility of pin access commits.
`-write_net_tracks`	Enable writing of net track assigments.

Check Pin Access#

This function checks pin access.

pin_access[-db_process_nodename][-bottom_routing_layerlayer][-top_routing_layerlayer][-via_access_layerlayer][-via_in_pin_bottom_layerlayer][-via_in_pin_top_layerlayer][-min_access_pointscount][-verboselevel][-distributed][-remote_hostrhost][-remote_portrport][-shared_volumevol][-cloud_sizesz]

Options#

Switch Name	Description
`-db_process_node`	Specify process node.
`-bottom_routing_layer`	Deprecated. Use the`set_routing_layers` command instead.
`-top_routing_layer`	Deprecated. Use the`set_routing_layers` command instead.
`-via_access_layer`	Refer to pin access argumentshere.
`-via_in_pin_bottom_layer`	Refer to pin access argumentshere.
`-via_in_pin_top_layer`	Refer to pin access argumentshere.
`-min_access_points`	Refer to pin access argumentshere.
`-verbose`	Sets verbose mode if the value is greater than 1, else non-verbose mode (must be integer, or error will be triggered.)
`-distributed`	Refer to distributed argumentshere.
`-remote_host`	Refer to distributed argumentshere.
`-remote_port`	Refer to distributed argumentshere.
`-shared_volume`	Refer to distributed argumentshere.
`-cloud_size`	Refer to distributed argumentshere.

Pin Access Arguments#

We have compiled all pin access related arguments in this section.

Switch Name	Description
`-via_access_layer`	Top via access layer name. Any pin on this layer or below can only be accessed through a via, disallowing planar access.
`-via_in_pin_bottom_layer`	Via-in pin bottom layer name. Used in conjunction with via_in_pin_top_layer to specify the layer range for via-in-pin rules.
`-via_in_pin_top_layer`	Via-in pin top layer name. Used in conjunction with via_in_pin_bottom_layer to specify the layer range for via-in-pin rules. For pins within this layer range, any via enclosure must be fully contained within the pin boundary and cannot extend beyond the pin edges.
`-min_access_points`	Minimum number of access points per pin.

Distributed Arguments#

We have compiled all distributed arguments in this section.

Note

Additional setup is required. Please refer to thisguide.

Switch Name	Description
`-distributed`	Enable distributed mode with Kubernetes and Google Cloud.
`-remote_host`	The host IP.
`-remote_port`	The value of the port to access from.
`-shared_volume`	The mount path of the nfs shared folder.
`-cloud_size`	The number of workers.

Useful Developer Commands#

If you are a developer, you might find these useful. More details can be found in thesource file or theswig file.

Command Name	Description
`detailed_route_set_default_via`	Set default via.
`detailed_route_set_unidirectional_layer`	Set unidirectional layer.
`step_dr`	Refer to function`detailed_route_step_drt`.
`check_drc`	Refer to function`check_drc_cmd`.

Example scripts#

Example script demonstrating how to run TritonRoute on a sample design ofgcdin the Nangate45 technology node.

# single machine example./test/gcd_nangate45.tcl# distributed example./test/gcd_nangate45_distributed.tcl

Regression tests#

There are a set of regression tests in./test. For more information, refer to thissection.

Simply run the following script:

./test/regression

Limitations#

FAQs#

Check outGitHub discussionabout this tool.

References#

Please cite the following paper(s) for publication:

A. B. Kahng, L. Wang and B. Xu, “TritonRoute: The Open Source DetailedRouter”, IEEE Transactions on Computer-Aided Design of Integrated Circuitsand Systems (2020), doi:10.1109/TCAD.2020.3003234.(.pdf)
A. B. Kahng, L. Wang and B. Xu, “The Tao of PAO: Anatomy of a Pin AccessOracle for Detailed Routing”, Proc. ACM/IEEE Design Automation Conf., 2020,pp. 1-6.(.pdf)

Authors#

TritonRoute was developed by graduate students Lutong Wang andBangqi Xu from UC San Diego, and serves as the detailed router in theOpenROAD project.

License#

BSD 3-Clause License. SeeLICENSE file.

Contents

Movatterモバイル変換

Detailed Routing

Contents

Detailed Routing#

Commands#

Detailed Route#

Options#

Developer arguments#

Detailed Route Debugging#

Options#

Check Pin Access#

Options#

Pin Access Arguments#

Distributed Arguments#

Useful Developer Commands#

Example scripts#

Regression tests#

Limitations#

FAQs#

References#

Authors#

License#

Detailed Routing #