Swift versus C clang

How the programs are written matters! Always look at the source code.

If the fastest programs are flagged * possible hand-written vector instructions or "unsafe" or naked ffi, does the host language matter? You might be more interested in the less optimised programs — more seconds, less gz source code.

fannkuch-redux
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
* C clang #6	2.25	8.88	2,941	1582	5.47
* C clang #4	13.38	13.39	2,351	1190	5.22
C clang #5	8.13	32.00—32.15	4,764	917	5.37
* Swift #3	8.22	32.50—32.61	13,808	1103	14.41
C clang #3	34.18	34.19—34.26	2,355	574	5.02
* C clang #2	8.70	34.15—34.33	2,945	1563	5.27
Swift #8	34.68	34.68—34.78	13,476	470	12.23
C clang #8	36.36	36.44—36.51	2,347	483	5.13
C clang	36.52	36.54—36.63	2,347	514	5.35
n-body
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
* C clang #9	2.20	2.20	2,417	1639	6.15
* C clang #5	4.86	4.86	2,470	1436	5.17
C clang #6	5.17	5.17	2,970	1186	5.42
C clang	5.38	5.39	2,978	1179	5.06
C clang #2	5.43	5.43	2,966	1270	5.25
* Swift #3	5.46	5.45—5.53	25,002	1688	14.30
* Swift #4	5.49	5.49	25,010	1361	15.19
* Swift #5	5.52	5.50—5.55	25,010	1372	15.67
* Swift #7	5.53	5.52	25,010	1333	14.58
* C clang #4	5.60	5.61	2,953	1398	6.30
C clang #8	5.70	5.56—6.19	2,961	1195	5.27
Swift #6	5.81	5.79—5.86	12,947	1213	13.99
C clang #3	6.13	6.13	2,966	1214	5.26
Swift #8	6.66	6.66	12,808	1285	12.73
C clang #7	6.78	6.80	2,966	1250	5.05
Swift	7.89	7.88	12,808	1210	13.77
Swift #9	287.49	287.49—288.02	24,867	1532	14.21
spectral-norm
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
* C clang #6	0.39	1.55	4,686	1203	6.45
* C clang #4	0.73	2.87	5,382	1145	5.66
* C clang #5	0.73	2.87—2.91	5,403	576	5.55
* C clang #2	0.74	4.30—7.09	5,288	941	6.43
Swift #8	5.36	5.35	24,936	411	15.00
C clang #8	5.41	5.42	3,211	389	5.15
Swift #3	1.45	5.71	13,705	607	13.91
C clang #3	1.45	5.75—5.79	5,423	470	5.58
* C clang #7	1.84	8.98—10.12	5,439	906	6.66
mandelbrot
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
C clang #9	1.24	4.92	36,811	700	5.32
* Swift #7	1.35	5.30	57,856	1147	15.57
* Swift #6	1.48	5.78	60,969	1147	15.74
C clang #5	1.54	6.10	37,044	788	5.35
* C clang #4	3.49	13.89—13.95	36,102	805	5.26
* C clang	3.51	13.95	35,643	828	5.65
* C clang #7	3.54	14.02—14.06	36,491	1000	5.49
* C clang #3	3.56	14.16—14.20	35,418	769	5.06
C clang #8	25.51	25.52	2,359	412	5.22
Swift #8	25.63	25.62	12,841	426	13.44
Swift	26.55	26.54	12,853	400	13.78
Swift #5	7.28	27.12	49,291	665	14.09
* C clang #6		Empty
* Swift #3		Bad Output
fasta
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
C clang #3	0.79	0.79	2,273	1469	4.57
C clang #5	1.20	1.20	2,204	1286	5.64
C clang #2	2.44	2.44	2,163	1299	5.14
C clang #6	1.04	3.05	5,272	1936	5.40
C clang #7	0.83	3.28—3.32	5,861	2276	5.29
C clang	3.47	3.47	2,392	1213	5.28
* Swift #2	2.24	4.74—5.94	13,767	1952	15.21
* Swift #3	2.20	5.37	39,313	2097	16.81
* Swift	5.43	5.42—5.47	12,640	1533	14.40
C clang #8	8.08	8.14—8.25	2,200	839	5.08
Swift #8	18.86	18.86—18.92	12,837	828	13.46
C clang #4		Empty
k-nucleotide
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
C clang	6.27	13.93—14.23	134,038	1512	6.01
* Swift #2	14.46	55.16—55.44	273,932	1373	14.99
Swift #8	167.99	175.66—188.61	904,810	658	14.96
Swift #7	225.53	231.92—242.63	649,970	607	14.99
Swift		Empty
reverse-complement
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
* C clang #7	0.45	0.61—0.67	514,220	1899	6.22
C clang #9	0.47	0.72	514,216	1551	5.13
C clang #2	1.17	1.70	1,021,891	757	5.17
C clang #5	1.97	2.03—2.09	1,020,813	654	5.16
* Swift	1.97	2.41	825,594	1293	16.00
* C clang #4	3.77	3.78	514,023	716	4.93
C clang #6	1.05	4.15—4.20	714,764	828	5.90
binary-trees [ Contentious. Different approaches. ]
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
C clang #2	1.66	5.23—6.05	176,116	816	5.77
C clang #3	1.91	5.90	138,719	842	5.90
C clang	17.72	17.78—18.29	271,938	660	5.20
C clang #5	9.25	33.42—33.59	361,689	914	4.96
Swift	18.32	54.27—54.38	763,609	720	15.54
Swift #4	17.69	55.61—57.68	733,131	772	15.64
Swift #5	18.99	56.13—58.05	764,781	813	14.50
Swift #2	18.36	58.30—64.86	733,131	822	15.77
Swift #3	18.24	58.63—59.13	733,000	868	14.57
* Swift #9		Empty
pidigits [ Contentious. Different libraries. ]
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
C clang #2	0.74	0.74	3,990	422	5.19
C clang	0.75	0.75	3,731	459	5.35
* Swift #2	0.76	0.75	14,238	606	13.58
regex-redux [ Contentious. Different libraries. ]
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
C clang #5	0.83	2.82	159,736	1403	5.40
C clang #2	3.22	3.22	106,783	1121	5.07
C clang #4	0.99	3.82—3.86	159,539	1237	5.11
C clang #3	1.76	4.34	109,867	1273	5.08
Swift #2	38.81	38.84—39.05	710,750	678	14.74
Swift	23.39	39.78—39.91	922,284	721	13.23
Swift #4	18.22	41.22—41.58	1,099,583	751	14.65
Swift	Swift version 6.0 (swift-6.0-RELEASE) Target: x86_64-unknown-linux-gnu
C clang	Ubuntu clang version 18.1.8 (11)