Rust 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	2,933	1582	5.56
* C clang #4	13.39	13.39	2,343	1190	5.32
* Rust #6	3.81	15.06	3,985	1260	11.92
Rust #4	6.94	27.12	3,985	1026	11.71
Rust #5	7.41	28.89	3,990	1023	11.79
C clang #5	8.10	32.01—32.15	4,792	917	5.61
* C clang #2	8.68	34.14—34.46	2,703	1563	5.59
C clang #3	34.14	34.19—34.26	2,351	574	5.16
Rust #2	9.19	36.04—36.08	3,723	1198	11.14
C clang #8	36.35	36.38—36.47	2,347	483	5.08
C clang	36.52	36.54—36.63	2,347	514	5.39
n-body
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
* Rust #9	2.19	1.90—3.09	3,023	1881	11.01
* C clang #9	2.20	2.20	2,494	1639	6.10
* Rust #7	3.24	3.24	2,937	1759	10.53
Rust #3	3.46	3.46	2,937	1774	10.62
Rust #2	3.65	3.65	3,031	1809	10.49
Rust #6	4.37	4.36—4.49	3,031	1796	10.86
* C clang #5	4.86	4.86	2,417	1436	5.03
* Rust #5	5.02	5.03	3,035	2224	10.61
Rust #4	5.13	4.99—5.53	3,039	1810	10.50
C clang #6	5.17	5.17	2,970	1186	5.19
C clang	5.38	5.40	2,974	1179	5.35
C clang #2	5.43	5.44	2,982	1270	5.30
Rust	5.52	5.50—5.60	3,027	1483	10.84
* C clang #4	5.60	5.61	2,941	1398	6.20
C clang #8	5.70	5.70—5.75	2,941	1195	5.20
C clang #3	6.13	6.13	2,978	1214	5.65
C clang #7	6.78	6.79	2,974	1250	5.16
spectral-norm
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
* C clang #6	0.39	1.52—1.56	4,706	1203	6.40
* C clang #5	0.73	2.87	5,206	576	5.85
* Rust #6	0.72	2.85	3,981	1132	12.60
Rust #4	0.72	2.85	4,047	823	12.00
Rust #5	0.72	2.86	4,018	1062	11.30
* Rust #2	0.72	2.86	4,145	1117	11.00
* Rust	0.72	2.86	4,104	1262	11.75
* C clang #4	0.73	2.88—2.92	5,366	1145	5.86
* C clang #2	0.73	4.15—6.50	5,411	941	6.35
* Rust #3	0.74	2.94	4,121	1060	10.92
C clang #8	5.41	5.42	3,211	389	5.20
C clang #3	1.45	5.74	5,390	470	5.53
* C clang #7	1.85	8.31—9.99	5,399	906	6.27
Rust #7		Empty
mandelbrot
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
Rust #4	0.95	3.78	35,598	1301	12.26
Rust #6	1.08	4.21	36,426	1338	12.65
Rust #7	1.10	4.34	35,906	763	12.32
Rust #2	1.10	4.36—4.52	35,754	770	12.80
Rust #5	1.12	4.38	36,311	725	12.27
Rust #3	1.15	4.57	14,615	1013	12.66
C clang #9	1.23	4.91	36,614	700	5.36
C clang #5	1.54	6.10	36,893	788	5.17
Rust	2.01	7.90	42,631	874	10.94
* C clang #4	3.49	13.85—13.93	36,458	805	5.13
* C clang	3.50	13.95	35,627	828	5.30
* C clang #7	3.53	14.02	36,758	1000	5.70
* C clang #3	3.56	14.16—14.22	35,484	769	5.23
C clang #8	25.48	25.50—25.55	2,359	412	5.04
* C clang #6		Empty
fasta
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
C clang #3	0.78	0.78	2,257	1469	5.10
C clang #5	1.20	1.20	2,208	1286	5.41
* Rust #7	0.78	1.55	4,772	2533	11.68
Rust #3	2.03	2.03	3,199	1235	10.95
C clang #2	2.44	2.44	2,200	1299	5.46
C clang #6	1.05	3.05	5,104	1936	5.36
Rust #9	0.94	3.20—3.33	5,534	1952	11.24
C clang #7	0.83	3.28—3.32	5,947	2276	5.40
Rust #2	0.95	3.46—3.50	5,554	1910	11.45
Rust #5	0.94	3.48—3.53	5,554	1963	12.19
C clang	3.47	3.47	2,396	1213	5.07
Rust #4	3.52	3.53	128,217	944	10.63
Rust #6	3.53	3.53	128,381	959	10.62
Rust	4.45	4.54—4.61	3,113	1240	11.09
C clang #8	8.09	8.19—8.30	2,200	839	4.95
C clang #4		Empty
k-nucleotide
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
Rust #7	2.57	8.13—8.39	139,088	1585	13.43
Rust #3	3.28	9.72—10.13	142,631	1549	11.91
Rust #6	2.79	10.06—10.15	165,048	1697	14.10
Rust #5	3.88	11.66—11.92	143,155	1745	12.40
C clang	6.34	13.99—14.10	134,189	1512	5.85
Rust #2	6.00	15.71—16.24	142,946	1350	11.85
Rust #9	6.33	17.72—18.82	141,099	1850	14.41
Rust #4	6.69	18.00—18.74	142,090	1755	13.13
Rust	21.08	64.42—65.12	161,219	1086	12.16
reverse-complement
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
* C clang #7	0.46	0.65	514,040	1899	6.27
C clang #9	0.48	0.72	514,277	1551	5.42
* Rust	0.55	0.85	512,963	2762	11.72
Rust #2	1.01	1.61	1,022,128	1332	11.04
Rust #3	1.02	1.72	1,022,034	1105	11.45
C clang #2	1.19	1.72	1,021,899	757	5.27
C clang #5	2.01	2.07—2.12	1,020,629	654	5.18
* C clang #4	3.79	3.80	514,073	716	5.07
C clang #6	1.08	4.26—4.30	699,249	828	5.14
binary-trees [ Contentious. Different approaches. ]
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
Rust #5	1.07	3.84—4.01	139,121	771	1.28
Rust #2	1.17	4.16—4.25	140,157	729	12.50
Rust #4	1.38	4.98—5.02	202,686	765	12.32
Rust #3	1.40	5.15—5.26	172,392	762	11.90
C clang #2	1.68	5.26—6.08	176,222	816	2.58
C clang #3	1.92	5.90	138,723	842	5.80
Rust	2.10	7.44	137,417	760	11.36
C clang	17.86	17.75—18.31	271,938	660	5.22
C clang #5	9.24	33.44—33.54	361,550	914	5.00
pidigits [ Contentious. Different libraries. ]
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
Rust #4	0.71	0.72	4,055	804	11.82
C clang #2	0.74	0.74	3,990	422	5.46
* Rust #2	0.75	0.75	4,387	1312	10.44
* Rust	0.75	0.75	4,243	1426	10.19
* Rust #3	0.75	0.75	4,510	1373	10.10
C clang	0.75	0.75	3,719	459	5.06
regex-redux [ Contentious. Different libraries. ]
	elapsed	Mean or 95% CI
source	secs	cpu secs	mem	gz	make
Rust #6	1.21	1.46	159,846	994	13.12
Rust #5	1.35	1.58	209,863	777	12.67
Rust	1.35	1.59—1.63	159,793	811	12.22
Rust #3	1.38	1.63	210,379	726	13.51
Rust #4	1.38	1.64	206,811	771	12.41
Rust #2	1.38	1.64	159,937	707	11.67
* Rust #7	0.78	2.00	157,442	2464	12.48
C clang #5	0.84	2.84	159,756	1403	5.28
C clang #2	3.23	3.23	106,799	1121	5.07
C clang #4	1.00	3.84—3.89	159,789	1237	5.30
C clang #3	1.76	4.33—4.37	109,871	1273	5.44
Rust	1.84.1 (e71f9a9a9 2025-01-27) LLVM version: 19.1.5
C clang	Ubuntu clang version 19.1.1 (1ubuntu1)