Benchmark PRs on PGLib IEEE 300

[cameronkhanpour]

Summary

• Run PR benchmarks on the PGLib IEEE 300 case instead of PowerModels' IEEE 30 fixture.
• Resolve the pinned case through PowerDiff's existing PGLib artifact.
• Remove the now-unused PowerModels benchmark dependency and fallback loader.

Why

The previous 30-bus case left several KKT benchmarks in the sub-microsecond range, which made PR-to-main comparisons noisy and less informative. IEEE 300 is large enough to expose meaningful runtime and allocation changes while remaining practical for routine pull request runs.

PEGASE 1354 was considered, but its dense AC switching Jacobian would occupy roughly 510 MiB per evaluation. IEEE 300 keeps that matrix near 22 MiB.

Impact

Benchmark results will report the 300-bus case across parser, DC OPF, and AC OPF groups. The workflow no longer installs PowerModels solely to find a test fixture.

Validation

• Loaded the benchmark script in a fresh Julia environment without PowerModels.
• Ran every benchmark once with samples=1, evals=1.
• julia --project=. -e "using Pkg; Pkg.test()" (2,916 assertions passed).
• Parsed .github/workflows/Benchmark.yml successfully.

Closes #61

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	f626352...	main / f626352...
ac_opf/kkt_jacobian/pglib_opf_case300_ieee.m	29.8 ± 1.9 ms	29.7 ± 0.95 ms	1.01 ± 0.07
ac_opf/kkt_param/pglib_opf_case300_ieee.m/switching	3.13 ± 0.75 ms	3.12 ± 0.52 ms	1 ± 0.29
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/cost_linear	1.11 ± 0.29 μs	1.21 ± 0.33 μs	0.92 ± 0.35
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/cost_quadratic	0.558 ± 0.18 μs	0.549 ± 0.18 μs	1.02 ± 0.47
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/demand	3.12 ± 0.44 μs	2.99 ± 0.47 μs	1.05 ± 0.22
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/flowlimit	7.7 ± 3.5 μs	7.5 ± 4 μs	1.03 ± 0.72
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/full	0.089 ± 0.021 ms	0.0848 ± 0.023 ms	1.05 ± 0.37
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/susceptance	6.25 ± 0.27 ms	5.82 ± 0.32 ms	1.07 ± 0.075
parser/pglib_opf_case300_ieee.m	0.694 ± 0.013 ms	0.694 ± 0.015 ms	1 ± 0.029
time_to_load	1.98 ± 0.02 s	1.96 ± 0.018 s	1.01 ± 0.013

Memory benchmarks

	main	f626352...	main / f626352...
ac_opf/kkt_jacobian/pglib_opf_case300_ieee.m	0.373 M allocs: 12.3 MB	0.373 M allocs: 12.3 MB	1
ac_opf/kkt_param/pglib_opf_case300_ieee.m/switching	14.8 k allocs: 26.2 MB	14.8 k allocs: 26.2 MB	1
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/cost_linear	6 allocs: 1.83 kB	6 allocs: 1.83 kB	1
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/cost_quadratic	6 allocs: 1.83 kB	6 allocs: 1.83 kB	1
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/demand	9 allocs: 12 kB	9 allocs: 12 kB	1
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/flowlimit	9 allocs: 16.3 kB	9 allocs: 16.3 kB	1
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/full	0.108 k allocs: 0.751 MB	0.108 k allocs: 0.751 MB	1
dc_opf/kkt_jacobian/pglib_opf_case300_ieee.m/susceptance	27.4 k allocs: 21.5 MB	27.4 k allocs: 21.5 MB	1
parser/pglib_opf_case300_ieee.m	0.082 k allocs: 4.7 kB	0.082 k allocs: 4.7 kB	1
time_to_load	0.149 k allocs: 11.1 kB	0.149 k allocs: 11.1 kB	1