Licence

This file is part of Corblivar.

Corblivar is a simulated-annealing-based floorplanning suite for 3D ICs, with special emphasis on structural planning of massive interconnects by block alignment.

Corblivar is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Corblivar is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Corblivar. If not, see http://www.gnu.org/licenses/.

Citation

If you find this tool useful, and apply it for your research and publications, please cite our papers:

Knechtel, J.; Young, E. F. Y. & Lienig, J. "Planning Massive Interconnects in 3D Chips" IEEE Trans. Comput.-Aided Des. Integr. Circuits Sys., 2015, DOI: http://dx.doi.org/10.1109/TCAD.2015.2432141
Knechtel, J.; Young, E. F. Y. & Lienig, J. "Structural Planning of 3D-IC Interconnects by Block Alignment" Proc. Asia South Pacific Des. Autom. Conf., pp. 53-60, 2014

Compile & Run

To compile and run Corblivar, you need the following tool

clang++ (at least v 3.1 is required; compiling w/ version 3.2 was tested)
gnuplot
octave
perl
cairosvg
a modified copy of the BU's HotSpot 3D-IC thermal analyzer; the code should be provided along with Corblivar or can be retrieved from https://github.com/jknechtel/HotSpot. Note that this code has to be compiled separately.

Usage

To use Corblivar, the following procedure should be followed

Configuration of HotSpot

see ../HotSpot/hotspot.config

Relevant are the specs for the heat sink and heat spreader; they should be adapted to reflect largest chip dimensions under consideration.

Also note that the helper script exp/HotSpot.sh relies on HotSpot being in ~/code/HotSpot; if your local setup differs, adapt the script accordingly.

Configuration of Corblivar

see exp/Corblivar.conf and exp/Technology.conf, or other examples in exp/configs/

Technology parameters like die dimensions and TSV sizes are configured in exp/Technology.conf

In exp/Corblivar.conf, the section "SA -- Layout generation options" can be used to configure the optimization heuristic. Reasonable values depend on the experiments under consideration.

The sections "SA -- Loop parameters" and "SA -- Temperature schedule parameters" control the runtime behaviour of the optimization. These values can impact the success rate, especially for ``complex'' experiments with many block-alignment requests and/or dense packing. The latter section, however, is considered to be applicable for different experiments---the adaptive SA-optimization schedule draws the cooling parameters somewhat robust since local minima in the solution space can be escaped easily by iterative temperature increases (cooling phase 3).

The section "SA -- Factors for second-phase cost function" controls the various optimization modules; the related values should be adapted to reflect the desired cost function. Note that zero values deactivate the respective optimization completely and thus allows to save runtime.

The section "Power blurring (thermal analysis) -- Default thermal-mask parameters" can be left as is; the related parametrization is done via separate scripts, as described in the next step.

Parametrization of Power-Blurring Thermal Analysis

see thermal_analysis_octave/ and doc/therma_analysis_octave.pdf

As indicated in 2), the thermal-mask parameters are determined separately. The related Octave scripts should be run whenever the 3D-IC setup changes notably, i.e., when the number of layers, the outline, the heatsink, and/or the (magnitude of) power consumption of the benchmarks changes.

To configure the Octave scripts, see thermal_analysis_octave/parameters.m Note that given default parameters should be applicable for most GSRC-benchmarks-based experiments.

To run the Octave scripts, either change directory to thermal_analysis_octave/ and start scripts from there (octave optimization.m BENCH CORBLIVAR.CONF), or copy the scripts from thermal_analysis_octave/ to separate working directories; see below and/or exp/run9.sh for further details.

The Octave scripts work roughly like this: first, generate an initial floorplan solution, used as a baseline reference; second, run HotSpot on this solution (note that specific values for heterogeneous TSV densities are already considered here); third, match the power-blurring temperature map to the HotSpot map via a local search; fourth, output the related power-blurring parameters for the best match, which describes the HotSpot estimate most closely. For further details, see documentation_Octave.pdf.

Note that Corblivar can model the thermal impact of both regular signal TSVs and vertical buses, i.e., large TSV groups. Regular signal TSVs are, however, only considered when the layout-generation option "Clustering of signal TSVs" is activated. Vertical buses are assumed to have tightest possible packing of multiple TSVs (100% TSV density) for the whole bus region, even if fewer TSVs would suffice for signal transmission.

Running Corblivar

see exp/run.sh or directly start ./Corblivar*

To run Corblivar, one can start the binary directly, for example from the exp/ folder as

../Corblivar BENCH CORBLIVAR.CONF benches/

The other option is to call Corblivar in a batch mode, as outlined in the scripts exp/run*.sh

Note that for generation of plotted data, one has to call the script exp/gp.sh afterwards in the related working directory.

Comments

The further comments below are for better understanding of the Corblivar tool and its structure

Various experiments can be started using exp/run*.sh; these scripts are not a complete set for running all experiments but rather a guideline for different setups.

The folder exp/benches/ includes MCNC (some are not working, i.e., have issues with their content), GSRC, and IBM-HB+ benchmarks, all in the GSRC format

The folder thermal_analysis_octave/ includes Octave scripts for the parameterization of the power-blurring-based thermal analysis; they can be also included e.g. in run*.sh scripts. Note that these scripts will produce temporary output data in thermal_analysis_octave/, i.e., you might want to copy thermal_analysis_octave/ into separate working directories for parallel execution of different experiments, to avoid mixed up data. See for example exp/run9.sh

The script exp/gp.sh delegates to gnuplot for generating various output plots, e.g., thermal map and floorplan, after running Corbilvar.

The script HotSpot.sh calls a (slightly modified) version of BU's 3D HotSpot program; the related code should be provided along with Corblivar.

The file exp/Corblivar.conf is a template for the config file required by Corblivar, further examples can be found in exp/configs/.

Settings in some scripts may rely on the folder ~/code ; putting ~/code/Corblivar along with ~/code/HotSpot is the default setup which should be working in any case.

Changelog

1.3.1

May 2015, commit f770ba1d2e56f9df6f3f0dab0d9e2b020e111928 minor updates and fixes

fixes related to handling aligmnet with RBOD, i.e., alignments for pre-fixed blocks
updates for TSV handling; put single TSVs (in net's bounding boxes' center) in case clustering is not applied

1.3.0

May 2015, commit 10098b4fe61b8f23e8d777c1039ef75b9523e024 considerable updates and fixes (interconnects handling, clustering, layout operations, HotSpot data, etc), new feature: routing-congestion estimation

added estimation of routing congestion; considering all wires, also connecting to TSVs
various fixes regarding clustering and related interconnects handling
improved accuracy for determination of interconnects; for TSVs, regular wires and massive busses
improved layout packing; added dedicated handling for outer blocks
improved handling TSV islands, greedy shifting to avoid overlaps
various fixes regarding gridding of HotSpot input-data; HotSpot errors due to conversion errors are now settled
updates and fixes handling of strictly aligned massive interconnects
updates and fixes for handling for intermediately failed alignmentsA
updates and fixes layout operations
various updates and cleanups for logging
various updates and cleanups for benchmarks and experimental setups

1.2.0

October 13, 2014, commit 3f770ef4302729f6aa253ecdb65d2ffbb6c2ffbb major updates (alignment encoding and handling, consideration of interconnects' HPWL), new features (clustering of signal TSVs and related hotspot determination), and various fixes and cleanups

added handling for TSV blocks
added feature; clustering of signal TSVs into vertical buses, related features like blob-detection-based hotspot determination and handling of vertical buses during thermal analysis
update alignment encoding; added global type (strict, flexible) and signals count
update alignment handling; added dedicated swap operations for failed alignments
update massive-interconnects handling; consider interconnects' weighted HPWL during optimization (for fair comparison and better final results)
updates folder structure
added Technology.conf; separate file for technology parameters
updates and cleanups classes, code structure, and namespace
updates experimental setups and configs
updates and fixes octave scripts for thermal analysis
updates and fixes HotSpot file generation
various further fixes and updates

1.1.1

May 7, 2014, commit bacb85a62a4b779cb94286ee3a1e946c19e234a1 updates, consideration of heterogeneous TSV densities

dropped deprecated handling of different masks
dropped dummy TSV handling
added handler for TSV densities considering both signal TSVs and vertical buses
Octave script now considers parameter for scaling down power in TSV regions
various minor updates and fixes

1.1.0

Nov 13, 2013, commit 1de2426d361595bbec4542e425c8eb74fecaf544 new feature, consideration of heterogeneous TSV densities

adapted power blurring for using different masks
added plotting of TSV-density maps
adapted HotSpot file handler
added dummy TSV handler
Octave script now considers determination of different masks
various minor updates and fixes

1.0.4

Aug 21, 2013, commit 44f573ed8f31654e6c07d6cc391cf528233f30bf fixes and updates, thermal analysis

1.0.3

Aug 1, 2013, commit 157d3c989ac20799d0e4efce8acf6b244a68a480 fix, compiling error for 64-bit libaries

1.0.2

Jul 29, 2013, commit 80029340de6e0d9fc97c705828671cbc4a26057c update, enable fixed-position block alignment

1.0.1

Jul 29, 2013, commit f583c3b77b4c67a7b11aacc117f0d436b5408d84 bugfixes and updates

update HotSpot BU to v 1.2
fixes calculation of thermal-related material properties
new class Chip contains all chip-related settings

1.0.0

Jul 22, 2013, commit 286b7917b05be13d3cbcdb4b837422baa00888ad initial public release

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