Copyright (C) 2014 Johann Knechtel, johann.knechtel@ifte.de, www.ifte.de
https://github.com/jknechtel/Corblivar
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/.
If you find this tool useful, and apply it for your research and publications, please cite our paper: 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
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-py3
- 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.
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.
- Configuration of Corblivar
see exp/Corblivar.conf or other examples in exp/configs
Most relevant is the section "3D-IC parameters", i.e., the number of layers in the IC stack and the fixed, common outline of these layers.
The section "SA -- Layout generation options" can be used to configure the optimization heuristic. Reasonable values depend on the experiments under consideration. Some options, like power-aware block handling, are to be considered carefully. The latter acts as a hard constraint such that blocks with high power consumption are placed in the upper layer, nearest to the heatsink. Note that this has the largest positive impact on thermal management, i.e., notably greater impact than thermal-aware placement within separate layers. This option may, however, render some specific block-alignment configurations infeasible. For example, two high-power blocks could then not be aligned across layers for embedding of vertical buses.
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 ``tight'' configurations 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 non-relevant since local minima in the solution space can be escaped easily by iterative temperature increases.
The section "SA -- Factors for second-phase cost function" controls the various optimization modules; the related values should be adapted to reflect the desired optimization cost function. Note that zero values deactivates the respective optimization completely and thus allows to save some 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_fitting/ and doc/therma_analysis_octave.pdf
As indicated in 2), the thermal-mask parameters are obtained 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_fitting/parameters.m
To run the Octave scripts, either change directory to thermal_analysis_fitting/ and start scripts from there (octave optimization.m BENCH CORBLIVAR.CONF), or copy the scripts from thermal_analysis_fitting/ to separate working directories; see below and/or exp/run9.sh for further details.
The Octave scripts work like this: first, generate a floorplan solution; second, run HotSpot on this solution (note that specific and heterogeneous TSV densities are 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 models the thermal impact of both regular signal TSVs and vertical buses, i.e., large TSV groups. Currently, regular signal TSVs are assumed placable within their related nets' bounding boxes, i.e., their superposed TSV densities are accordingly spread across the whole 3D-IC. Also, 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.
The further comments below are for 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_fitting/ 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_fitting/, i.e., you might want to copy thermal_analysis_fitting/ 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.
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
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
Aug 21, 2013, commit 44f573ed8f31654e6c07d6cc391cf528233f30bf fixes and updates, thermal analysis
Aug 1, 2013, commit 157d3c989ac20799d0e4efce8acf6b244a68a480 fix, compiling error for 64-bit libaries
Jul 29, 2013, commit 80029340de6e0d9fc97c705828671cbc4a26057c update, enable fixed-position block alignment
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
Jul 22, 2013, commit 286b7917b05be13d3cbcdb4b837422baa00888ad initial public release