| Issue |
128087
|
| Summary |
Poor performance of performance-unnecessary-value-param in clang-tidy 19.1.7
|
| Labels |
clang-tidy
|
| Assignees |
|
| Reporter |
roblub
|
After upgrading clang-tidy from version 18.1.6 to 19.1.7 I noticed that `performance-unnecessary-value-param` got really slow.
I run with `clang-tidy --enable-check-profile` on our code base, once with the old version, and once with the new one. Then I grepped entries of this check, sorted them by the first field, and please see top 20 entries from each version:
- clang-tidy 19.1.7:
```
1296.1571 ( 92.3%) 1.6836 ( 3.6%) 1297.8407 ( 89.4%) 1301.2990 ( 89.3%) performance-unnecessary-value-param
943.5278 ( 86.0%) 4.0867 ( 6.5%) 947.6145 ( 81.6%) 959.5694 ( 81.5%) performance-unnecessary-value-param
866.4393 ( 91.0%) 0.6227 ( 1.6%) 867.0620 ( 87.6%) 867.1579 ( 87.6%) performance-unnecessary-value-param
650.7637 ( 81.9%) 3.9667 ( 6.8%) 654.7304 ( 76.7%) 660.7008 ( 76.7%) performance-unnecessary-value-param
632.6522 ( 83.4%) 1.3317 ( 2.7%) 633.9839 ( 78.4%) 637.5449 ( 78.5%) performance-unnecessary-value-param
592.1411 ( 82.4%) 1.1224 ( 2.3%) 593.2635 ( 77.4%) 595.2981 ( 77.4%) performance-unnecessary-value-param
574.6037 ( 80.0%) 7.1497 ( 11.5%) 581.7534 ( 74.5%) 594.6721 ( 74.7%) performance-unnecessary-value-param
555.9572 ( 85.2%) 0.5483 ( 1.4%) 556.5055 ( 80.3%) 556.5736 ( 80.3%) performance-unnecessary-value-param
549.7090 ( 81.4%) 0.8889 ( 1.7%) 550.5980 ( 75.8%) 551.1463 ( 75.7%) performance-unnecessary-value-param
543.0547 ( 79.6%) 2.9457 ( 5.3%) 546.0004 ( 74.0%) 550.6407 ( 73.9%) performance-unnecessary-value-param
535.2278 ( 80.0%) 1.2093 ( 2.4%) 536.4371 ( 74.5%) 539.3148 ( 74.4%) performance-unnecessary-value-param
526.2376 ( 79.6%) 1.1839 ( 2.3%) 527.4214 ( 74.0%) 531.4533 ( 73.9%) performance-unnecessary-value-param
501.3134 ( 77.1%) 2.2074 ( 3.7%) 503.5208 ( 70.9%) 513.0346 ( 70.9%) performance-unnecessary-value-param
500.1112 ( 79.7%) 2.3116 ( 4.6%) 502.4228 ( 74.2%) 510.7616 ( 74.2%) performance-unnecessary-value-param
497.1975 ( 87.5%) 0.6075 ( 2.1%) 497.8050 ( 83.4%) 498.6758 ( 83.3%) performance-unnecessary-value-param
488.6909 ( 81.5%) 0.8534 ( 1.9%) 489.5443 ( 76.0%) 491.9533 ( 76.0%) performance-unnecessary-value-param
473.3286 ( 80.9%) 2.4528 ( 5.3%) 475.7814 ( 75.3%) 478.7844 ( 75.3%) performance-unnecessary-value-param
471.0853 ( 81.0%) 0.7795 ( 1.7%) 471.8648 ( 75.4%) 473.7543 ( 75.3%) performance-unnecessary-value-param
467.9987 ( 77.3%) 2.6716 ( 4.9%) 470.6703 ( 71.3%) 480.3696 ( 71.4%) performance-unnecessary-value-param
467.5921 ( 79.2%) 1.1558 ( 2.4%) 468.7479 ( 73.3%) 470.5755 ( 73.2%) performance-unnecessary-value-param
```
- clang-tidy 18.1.6:
```
14.3213 ( 9.3%) 0.2375 ( 0.6%) 14.5588 ( 7.4%) 14.5539 ( 7.4%) performance-unnecessary-value-param
12.1474 ( 4.4%) 0.3959 ( 0.5%) 12.5433 ( 3.6%) 12.5363 ( 3.6%) performance-unnecessary-value-param
11.1302 ( 4.3%) 0.3941 ( 0.6%) 11.5243 ( 3.5%) 11.5181 ( 3.5%) performance-unnecessary-value-param
11.0908 ( 4.6%) 0.3859 ( 0.6%) 11.4767 ( 3.7%) 11.4680 ( 3.7%) performance-unnecessary-value-param
10.9081 ( 5.1%) 0.3449 ( 0.6%) 11.2529 ( 4.1%) 11.2460 ( 4.1%) performance-unnecessary-value-param
10.9071 ( 4.0%) 0.3874 ( 0.6%) 11.2945 ( 3.3%) 11.2952 ( 3.3%) performance-unnecessary-value-param
10.3415 ( 3.9%) 0.4229 ( 0.6%) 10.7644 ( 3.2%) 10.9564 ( 3.2%) performance-unnecessary-value-param
10.0487 ( 4.5%) 0.3539 ( 0.6%) 10.4026 ( 3.6%) 10.4265 ( 3.6%) performance-unnecessary-value-param
9.8498 ( 4.6%) 0.3350 ( 0.6%) 10.1848 ( 3.7%) 10.5083 ( 3.8%) performance-unnecessary-value-param
9.6022 ( 4.4%) 0.3496 ( 0.6%) 9.9518 ( 3.6%) 9.9516 ( 3.5%) performance-unnecessary-value-param
9.3159 ( 4.5%) 0.3253 ( 0.6%) 9.6412 ( 3.7%) 9.6373 ( 3.7%) performance-unnecessary-value-param
9.1873 ( 4.4%) 0.3463 ( 0.6%) 9.5336 ( 3.6%) 9.5281 ( 3.6%) performance-unnecessary-value-param
9.0140 ( 3.7%) 0.3728 ( 0.6%) 9.3868 ( 3.0%) 9.3801 ( 3.0%) performance-unnecessary-value-param
8.9893 ( 4.0%) 0.3648 ( 0.6%) 9.3541 ( 3.3%) 9.3842 ( 3.3%) performance-unnecessary-value-param
8.8615 ( 3.9%) 0.3696 ( 0.6%) 9.2311 ( 3.2%) 9.3386 ( 3.2%) performance-unnecessary-value-param
8.6921 ( 3.9%) 0.3637 ( 0.6%) 9.0557 ( 3.2%) 9.2582 ( 3.0%) performance-unnecessary-value-param
8.5388 ( 4.3%) 0.3112 ( 0.6%) 8.8500 ( 3.5%) 8.8450 ( 3.5%) performance-unnecessary-value-param
8.5110 ( 3.8%) 0.3473 ( 0.6%) 8.8582 ( 3.1%) 8.8568 ( 3.1%) performance-unnecessary-value-param
8.4446 ( 4.0%) 0.3497 ( 0.6%) 8.7943 ( 3.2%) 8.7876 ( 3.2%) performance-unnecessary-value-param
8.3555 ( 4.6%) 0.2681 ( 0.5%) 8.6236 ( 3.7%) 8.6190 ( 3.7%) performance-unnecessary-value-param
```
As you can see the performance impact of the new version is really huge. Our jenkins job that previously (with clang-tidy 18) used to finish in about 2 hours, now (with clang 19) reached 8-hour timeout configured inside the job. After disabling this check, the job execution time went back to ~2 hours.
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