ci(codspeed): pin polars to one thread in the memory job by FabianHofmann · Pull Request #980 · PyPSA/linopy

FabianHofmann · 2026-09-24T14:49:33Z

Note

The following content was generated by AI.

Sets POLARS_MAX_THREADS=1 on the CodSpeed memory job.

Polars allocates native memory per worker thread, so the peak memory of the polars-based benchmarks (e.g. test_to_lp) depends on the core count of the ubuntu-latest runner. That produced a false regression on #974 (test_to_lp[nodal_balance-severity=0], 3.3 → 3.7 MB), for a legacy dense model that the PR's code does not touch.

Measurements (master 38fbd4a vs feat/csr-boundaries a817a5e, write_lp only)

tracemalloc (Python heap), nodal_balance: 0.959 MB on both after the first call.
memray with POLARS_MAX_THREADS=1: peaks and total allocations identical byte for byte across revisions and repeated processes.
memray with the default thread pool: the same revision swings between 3.5 and 12.8 MB across processes.

The walltime job is left untouched, since thread parallelism there is part of what is measured.

github-actions · 2026-09-24T14:53:05Z

Build cost — v1 vs legacy

v1 build peak & time relative to legacy, on this commit — not a comparison against master (that is CodSpeed).

peak — v1 / legacy	time — v1 / legacy

Full table (time + peak, mean)

benchmarks/drivers/test_build.py::test_build[basic-n=10]
                 time (s)         peak (KiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)   0.0906 (1.07)   │   15.03 (1.00) 
 (v1)       0.08449 (1.0)   │    15.00 (1.0) 

benchmarks/drivers/test_build.py::test_build[basic-n=250]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.09676 (1.10)   │   12.04 (1.00) 
 (v1)        0.08824 (1.0)   │    12.04 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=0]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.03878 (1.08)   │   15.20 (1.0) 
 (v1)         0.0358 (1.0)   │   15.20 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=100]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.05528 (1.05)   │   44.93 (1.0) 
 (v1)        0.05253 (1.0)   │   44.93 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=50]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.04195 (1.08)   │   11.51 (1.0) 
 (v1)        0.03899 (1.0)   │   11.51 (1.0) 

benchmarks/drivers/test_build.py::test_build[expression_arithmetic-n=10]
                 time (s)         peak (KiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)    0.101 (1.06)   │   24.34 (1.06) 
 (v1)       0.09555 (1.0)   │    23.04 (1.0) 

benchmarks/drivers/test_build.py::test_build[expression_arithmetic-n=250]
                 time (s)         peak (MiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)   0.1104 (1.06)   │   16.12 (1.00) 
 (v1)        0.1038 (1.0)   │    16.12 (1.0) 

benchmarks/drivers/test_build.py::test_build[knapsack-n=10000]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.02392 (1.06)   │   752.18 (1.10) 
 (v1)        0.02255 (1.0)   │    685.15 (1.0) 

benchmarks/drivers/test_build.py::test_build[knapsack-n=100]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.02334 (1.05)   │   3.12 (1.33) 
 (v1)        0.02214 (1.0)   │    2.34 (1.0) 

benchmarks/drivers/test_build.py::test_build[kvl_cycles-severity=0]
                  time (s)          peak (MiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.06334 (1.20)   │   126.16 (1.44) 
 (v1)         0.0527 (1.0)   │     87.71 (1.0) 

benchmarks/drivers/test_build.py::test_build[kvl_cycles-severity=100]
                  time (s)          peak (MiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.06294 (1.21)   │   126.16 (1.44) 
 (v1)        0.05201 (1.0)   │     87.71 (1.0) 

benchmarks/drivers/test_build.py::test_build[kvl_cycles-severity=50]
                  time (s)          peak (MiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.06305 (1.21)   │   126.16 (1.44) 
 (v1)        0.05223 (1.0)   │     87.71 (1.0) 

benchmarks/drivers/test_build.py::test_build[masked-n=100]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.05499 (1.00)   │    715.12 (1.0) 
 (v1)        0.05487 (1.0)   │   787.73 (1.10) 

benchmarks/drivers/test_build.py::test_build[masked-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.05311 (1.07)   │   4.54 (1.27) 
 (v1)        0.04973 (1.0)   │    3.57 (1.0) 

benchmarks/drivers/test_build.py::test_build[merge_balance-severity=0]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.3793 (1.02)   │   704.12 (1.09) 
 (v1)        0.3719 (1.0)   │    643.85 (1.0) 

benchmarks/drivers/test_build.py::test_build[merge_balance-severity=100]
                 time (s)        peak (MiB) 
 name                mean   │          mean 
────────────────────────────────────────────
 (legacy)   0.4024 (1.03)   │   18.34 (1.0) 
 (v1)         0.392 (1.0)   │   18.34 (1.0) 

benchmarks/drivers/test_build.py::test_build[merge_balance-severity=50]
                 time (s)       peak (MiB) 
 name                mean   │         mean 
───────────────────────────────────────────
 (legacy)   0.3941 (1.03)   │   9.54 (1.0) 
 (v1)        0.3843 (1.0)   │   9.54 (1.0) 

benchmarks/drivers/test_build.py::test_build[milp-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.07484 (1.07)   │   3.77 (1.12) 
 (v1)        0.06987 (1.0)   │    3.37 (1.0) 

benchmarks/drivers/test_build.py::test_build[milp-n=50]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.0766 (1.08)   │   216.59 (1.10) 
 (v1)       0.07097 (1.0)   │    196.23 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance-severity=0]
                  time (s)         peak (KiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.03897 (1.11)   │   938.49 (1.0) 
 (v1)        0.03499 (1.0)   │   938.49 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance-severity=100]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)   0.03973 (1.09)   │   9.66 (1.0) 
 (v1)        0.03651 (1.0)   │   9.66 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance-severity=50]
                 time (s)       peak (MiB) 
 name                mean   │         mean 
───────────────────────────────────────────
 (legacy)   0.0394 (1.10)   │   5.32 (1.0) 
 (v1)       0.03573 (1.0)   │   5.32 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=0]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)    0.02192 (1.0)   │   1.28 (1.0) 
 (v1)       0.02206 (1.01)   │   1.28 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=100]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)    0.02132 (1.0)   │   1.28 (1.0) 
 (v1)       0.02138 (1.00)   │   1.28 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=50]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)     0.0212 (1.0)   │   1.28 (1.0) 
 (v1)       0.02134 (1.01)   │   1.28 (1.0) 

benchmarks/drivers/test_build.py::test_build[piecewise-n=1000]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.1901 (1.04)   │   946.85 (1.06) 
 (v1)        0.1822 (1.0)   │    891.54 (1.0) 

benchmarks/drivers/test_build.py::test_build[piecewise-n=10]
                 time (s)         peak (KiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)   0.1858 (1.05)   │   12.01 (1.00) 
 (v1)        0.1764 (1.0)   │    11.99 (1.0) 

benchmarks/drivers/test_build.py::test_build[qp-n=1000]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.0475 (1.06)   │   147.70 (1.06) 
 (v1)       0.04478 (1.0)   │    139.87 (1.0) 

benchmarks/drivers/test_build.py::test_build[qp-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.04734 (1.06)   │   2.60 (1.09) 
 (v1)        0.04475 (1.0)   │    2.38 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=0]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.03986 (1.09)   │   696.75 (1.03) 
 (v1)        0.03657 (1.0)   │    673.70 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=100]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.08267 (1.01)   │   137.97 (1.0) 
 (v1)        0.08169 (1.0)   │   137.97 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=50]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.06078 (1.09)   │   69.22 (1.0) 
 (v1)        0.05573 (1.0)   │   69.22 (1.0) 

benchmarks/drivers/test_build.py::test_build[sos-n=1000]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.04544 (1.10)   │   402.33 (1.00) 
 (v1)        0.04148 (1.0)   │    402.30 (1.0) 

benchmarks/drivers/test_build.py::test_build[sos-n=10]
                 time (s)        peak (KiB) 
 name                mean   │          mean 
────────────────────────────────────────────
 (legacy)   0.0443 (1.08)   │   3.19 (1.19) 
 (v1)         0.041 (1.0)   │    2.69 (1.0) 

benchmarks/drivers/test_build.py::test_build[sparse_network-n=10]
                  time (s)         peak (KiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.04975 (1.07)   │   29.00 (1.54) 
 (v1)         0.0463 (1.0)   │    18.84 (1.0) 

benchmarks/drivers/test_build.py::test_build[sparse_network-n=250]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.05932 (1.08)   │   37.95 (1.43) 
 (v1)        0.05475 (1.0)   │    26.51 (1.0) 

benchmarks/drivers/test_build.py::test_build[storage-n=10]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)    0.09351 (1.0)   │    410.93 (1.0) 
 (v1)       0.09746 (1.04)   │   427.84 (1.04) 

benchmarks/drivers/test_build.py::test_build[storage-n=250]
                 time (s)         peak (MiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)   0.09904 (1.0)   │     9.94 (1.0) 
 (v1)       0.1048 (1.06)   │   10.22 (1.03)

📊 Interactive plots + CSV: download the semantics-report-v1-vs-legacy artifact from this run.

_{Report-only · not a gate · refreshed on every push · obsolete once legacy is dropped.}

codspeed · 2026-09-24T14:53:18Z

Merging this PR will regress 1 benchmark

⚡ 16 improved benchmarks
❌ 1 regressed benchmark
✅ 164 untouched benchmarks
⏩ 181 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	`BASE`	`HEAD`	Efficiency
❌	`test_to_lp[expression_arithmetic-n=250]`	42.8 MB	50.1 MB	-14.59%
⚡	`test_to_lp[qp-n=1000]`	2,646.5 KB	795.3 KB	×3.3
⚡	`test_to_lp[masked-n=100]`	2,793.7 KB	892.7 KB	×3.1
⚡	`test_to_lp[milp-n=50]`	2,760 KB	885.3 KB	×3.1
⚡	`test_to_lp[sos-n=1000]`	3 MB	1.4 MB	×2.2
⚡	`test_to_lp[expression_arithmetic-n=10]`	1,339.1 KB	691.1 KB	+93.76%
⚡	`test_to_lp[sparse_network-n=10]`	1,337.7 KB	695.6 KB	+92.3%
⚡	`test_to_lp[storage-n=10]`	2.9 MB	1.6 MB	+78.9%
⚡	`test_to_lp[piecewise-n=1000]`	3 MB	1.9 MB	+60.75%
⚡	`test_to_lp[rolling-severity=0]`	3.1 MB	2 MB	+57.33%
⚡	`test_to_lp[cumsum-severity=50]`	62.3 MB	43.1 MB	+44.74%
⚡	`test_to_lp[knapsack-n=10000]`	3 MB	2.1 MB	+40.41%
⚡	`test_to_lp[cumsum-severity=100]`	208.9 MB	160.9 MB	+29.83%
⚡	`test_to_lp[rolling-severity=50]`	429.9 MB	333.9 MB	+28.76%
⚡	`test_to_lp[rolling-severity=100]`	274.6 MB	227 MB	+20.97%
⚡	`test_to_lp[kvl_cycles-severity=0]`	280.9 MB	232.9 MB	+20.61%
⚡	`test_to_lp[kvl_cycles-severity=50]`	141.6 MB	117.6 MB	+20.41%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

_{Comparing ci/codspeed-polars-single-thread (22e8fdf) with master (14f601e)²}

181 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
No successful run was found on master (1a355c1) during the generation of this report, so 14f601e was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

ci(codspeed): pin polars to one thread in the memory job

4441c71

FabianHofmann added 2 commits September 25, 2026 07:14

Merge branch 'master' into ci/codspeed-polars-single-thread

180a989

Merge branch 'master' into ci/codspeed-polars-single-thread

22e8fdf

FabianHofmann merged commit bee7d1f into master Sep 25, 2026
20 of 21 checks passed

FabianHofmann deleted the ci/codspeed-polars-single-thread branch September 25, 2026 06:03

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ci(codspeed): pin polars to one thread in the memory job - #980

ci(codspeed): pin polars to one thread in the memory job#980
FabianHofmann merged 3 commits into
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FabianHofmann commented Sep 24, 2026

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FabianHofmann commented Sep 24, 2026

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Build cost — v1 vs legacy

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Merging this PR will regress 1 benchmark

Performance Changes

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