Add Hybrid Updating Strategy (HUS)

[diriLin]

No description provided.

[eddieh-xlnx]

This PR brings in the Hybrid Updating Strategy technique as described in:

@inproceedings{zang2024parallel,
  title={An Open-Source Fast Parallel Routing Approach for Commercial FPGAs},
  author={Zang, Xinshi and Lin, Wenhao and Lin, Shiju and Liu, Jinwei and Young, Evangeline FY},
  booktitle={Proceedings of the Great Lakes Symposium on VLSI 2024},
  year={2024}
}

Currently, this strategy is disabled by default and can be enabled using the --hus parameter, with further parameters to tune its behaviour.

In a nutshell, this technique reduces the growth of used nodes' present cost and instead increases the growth of overused nodes' historical cost --- with a view to reducing the runtime required to resolve conflicts in particularly congested designs --- once a number of thresholds relating to the number of congested connections and congested nodes are met.

On the 28 FPGA24 Routing Contest benchmarks, 7 of them triggered the threshold for HUS to activate (the rest are unaffected).

Summary is (geomean values):

• Non timing driven: 57% end-to-end wall time improvement
• Timing driven: 28% end-to-end wall time improvement, 15% critical path delay improvement

---

Data:

Wall time (non timing driven)	Baseline	--hus	Speedup
boom_med_pb	250.27	214.62	1.17
boom_soc	1392.01	1330.72	1.05
boom_soc_v2	5249	2219.67	2.36
mlcad_d181	4309	1383.67	3.11
mlcad_d181_lefttwo3rds	1896.25	819.81	2.31
rapidwright_picoblazearray	195.81	200.81	0.98
vtr_mcml	270.5	232.44	1.16
Geomean			1.57

Wall time (timing driven)	Baseline	--hus	Speedup
boom_med_pb	286.29	266.44	1.07
boom_soc	4057	4149	0.98
boom_soc_v2	6410	4560	1.41
mlcad_d181	4870	1977.61	2.46
mlcad_d181_lefttwo3rds	2293.41	1329.57	1.72
rapidwright_picoblazearray	283.43	328.71	0.86
vtr_mcml	343.94	336.91	1.02
Geomean			1.28

Critical path delay* (timing driven)	Baseline	--hus	Improvement
boom_med_pb	11038	9208	1.20
boom_soc	22282	20170	1.10
boom_soc_v2	15504	11982	1.29
mlcad_d181	9760	8317	1.17
mlcad_d181_lefttwo3rds	8667	7722	1.12
rapidwright_picoblazearray	3108	2796	1.11
vtr_mcml	8977	8323	1.08
Geomean			1.15

(* with timing closure guarantee value)