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Enable LTO on macOS ARM64 - #937

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ofek merged 7 commits into
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lto
Nov 17, 2025
Merged

Enable LTO on macOS ARM64#937
ofek merged 7 commits into
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lto

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@ofek ofek commented Nov 15, 2025 •
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Full LTO seems to cause a regression so this uses ThinLTO only on macOS (Clang) and only on ARM64. Here are the results of a few runs (the Intel runners just seem terrible):

Before

ARM64

encode: 145.9584 / decode: 351.2980

https://github.com/jcrist/msgspec/actions/runs/19412999871/job/55537240877

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS (Kops/s) Rounds Iterations
encode 130.4833 (1.0) 1,755.7709 (1.0) 153.0818 (1.0) 42.0774 (1.0) 145.9584 (1.0) 14.0292 (1.0) 446;834 6.5325 (1.0) 10000 10
decode 324.3583 (2.49) 10,951.2000 (6.24) 374.9843 (2.45) 154.3808 (3.67) 351.2980 (2.41) 20.2022 (1.44) 246;1309 2.6668 (0.41) 10000 10
encode: 143.2750 / decode: 354.1458

https://github.com/jcrist/msgspec/actions/runs/19412999871/job/55539651179

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS (Kops/s) Rounds Iterations
encode 130.3250 (1.0) 2,596.3542 (1.0) 154.4214 (1.0) 50.5128 (1.0) 143.2750 (1.0) 13.8417 (1.0) 471;1029 6.4758 (1.0) 10000 10
decode 323.7542 (2.48) 4,192.2167 (1.61) 375.4091 (2.43) 119.6400 (2.37) 354.1458 (2.47) 34.9271 (2.52) 225;631 2.6638 (0.41) 10000 10

x86_64

encode: 228.6268 / decode: 729.5701

https://github.com/jcrist/msgspec/actions/runs/19412999871/job/55537240884

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS (Kops/s) Rounds Iterations
encode 206.4159 (1.0) 7,320.7824 (1.61) 250.7420 (1.0) 94.9931 (1.0) 228.6268 (1.0) 36.5537 (1.0) 722;1198 3.9882 (1.0) 10000 10
decode 694.9477 (3.37) 4,550.2093 (1.0) 749.2888 (2.99) 110.4365 (1.16) 729.5701 (3.19) 49.4375 (1.35) 498;662 1.3346 (0.33) 10000 10
encode: 230.9933 / decode: 757.6821

https://github.com/jcrist/msgspec/actions/runs/19412999871/job/55539352389

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS (Kops/s) Rounds Iterations
encode 210.2697 (1.0) 5,402.5395 (1.0) 251.5679 (1.0) 100.4256 (1.0) 230.9933 (1.0) 43.8295 (1.0) 340;569 3.9751 (1.0) 10000 10
decode 697.6369 (3.32) 14,816.0169 (2.74) 807.6615 (3.21) 318.6815 (3.17) 757.6821 (3.28) 103.2592 (2.36) 235;698 1.2381 (0.31) 10000 10

After

ARM64

encode: 137.4250 / decode: 341.0833

https://github.com/jcrist/msgspec/actions/runs/19413142685/job/55537726515

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS (Kops/s) Rounds Iterations
encode 125.5625 (1.0) 1,878.1959 (1.26) 146.3765 (1.0) 53.2579 (1.0) 137.4250 (1.0) 3.5416 (1.0) 378;1460 6.8317 (1.0) 10000 10
decode 309.8791 (2.47) 1,487.6791 (1.0) 351.2185 (2.40) 71.5229 (1.34) 341.0833 (2.48) 21.1479 (5.97) 509;788 2.8472 (0.42) 10000 10
encode: 143.0917 / decode: 341.9875

https://github.com/jcrist/msgspec/actions/runs/19413142685/job/55539646141

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS (Kops/s) Rounds Iterations
encode 125.4333 (1.0) 1,788.0458 (1.0) 148.8024 (1.0) 41.2471 (1.0) 143.0917 (1.0) 14.7687 (1.0) 396;575 6.7203 (1.0) 10000 10
decode 303.9750 (2.42) 7,741.4625 (4.33) 375.3218 (2.52) 174.8312 (4.24) 341.9875 (2.39) 24.7896 (1.68) 493;1304 2.6644 (0.40) 10000 10

x86_64

encode: 224.2774 / decode: 690.9108

https://github.com/jcrist/msgspec/actions/runs/19413142685/job/55537726518

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS (Kops/s) Rounds Iterations
encode 207.8972 (1.0) 8,588.2149 (1.0) 253.7614 (1.0) 145.7307 (1.0) 224.2774 (1.0) 52.2173 (1.83) 290;703 3.9407 (1.0) 10000 10
decode 684.0644 (3.29) 14,789.9789 (1.72) 749.2749 (2.95) 312.8542 (2.15) 690.9108 (3.08) 28.4929 (1.0) 386;1463 1.3346 (0.34) 10000 10
encode: 339.4682 / decode: 924.6652

https://github.com/jcrist/msgspec/actions/runs/19413142685/job/55539486694

Name (time in us) Min Max Mean StdDev Median IQR Outliers OPS Rounds Iterations
encode 256.4145 (1.0) 29,541.7157 (3.10) 415.5266 (1.0) 584.9506 (1.74) 339.4682 (1.0) 129.0764 (1.0) 243;649 2,406.5850 (1.0) 10000 10
decode 780.7286 (3.04) 9,538.8675 (1.0) 1,033.4723 (2.49) 336.9571 (1.0) 924.6652 (2.72) 247.0121 (1.91) 866;452 967.6118 (0.40) 10000 10

@ofek
ofek force-pushed the lto branch 2 times, most recently from 9a3f12f to 7d7edee Compare November 16, 2025 15:52
@ofek
ofek marked this pull request as ready for review November 17, 2025 06:27
@ofek ofek changed the title Enable LTO on Linux and macOS Enable LTO on macOS ARM64 Nov 17, 2025
@ofek
ofek merged commit e72caf3 into main Nov 17, 2025
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@ofek
ofek deleted the lto branch November 17, 2025 06:30
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