1brc-walkthrough

The step-by-step walkthrough over 1brc challenge. See: https://github.com/artsiomkorzun/1brc-walkthrough/blob/main/Walkthrough.md

Prerequisites

Install Open JDK and GraalVM JDK using sdkman:

curl -s "https://get.sdkman.io" | bash
source "$HOME/.sdkman/bin/sdkman-init.sh"
sdk install java 21.0.2-open
sdk install java 21.0.2-graal

Install toolchain for GraalVM native-image: https://www.graalvm.org/22.0/reference-manual/native-image/#prerequisites.

Install hyperfine: https://github.com/sharkdp/hyperfine.

Run

 # tests might fail because they are run in one jvm, some solutions do not cleanup resources
./gradlew clean build -x test
 # generates 413 and 10k files
./generate-all.sh
 # evaluates 413 and 10k cases with all solutions
./eval-all.sh 

Results

Results are collected using hyperfine with 3 warmups and 10 measurements.

AWS c7a.4xlarge

• CPU: AMD EPYC 9R14
• MEM: DDR5 4800 MT/s 32 GB
• AFFINITY: 0-7

#	Change	Time (413)	Reduction (413)	Time (10k)	Reduction (10k)
00	Baseline	125.650 ± 0.740	0.0	160.107 ± 1.963	0.0
01	Substring	104.383 ± 0.363	-16.93	132.624 ± 1.320	-17.17
02	NoGarbage	41.824 ± 0.101	-59.93	61.337 ± 0.152	-53.75
03	DirectBuffer	40.261 ± 0.119	-3.73	56.018 ± 0.183	-8.67
04	MappedSegment	39.868 ± 0.338	-0.98	57.840 ± 0.297	3.25
05	Parallelism	5.583 ± 0.378	-86.00	8.018 ± 0.385	-86.14
06	HashWhileParsing	5.212 ± 0.466	-6.64	7.649 ± 0.933	-4.59
07	SimpleMap	4.915 ± 0.280	-5.70	7.211 ± 0.829	-5.73
08	BranchyTemperature	4.220 ± 0.181	-14.14	6.623 ± 0.555	-8.15
09	UnsafeParsing	3.861 ± 0.220	-8.51	6.035 ± 0.574	-8.88
10	NoKeyCopy	3.416 ± 0.055	-11.51	5.207 ± 0.023	-13.72
11	SwarStation	2.059 ± 0.070	-39.74	7.042 ± 0.122	35.26
12	SwarTemperature	1.798 ± 0.021	-12.67	6.865 ± 0.167	-2.52
13	BetterHash	1.776 ± 0.038	-1.22	2.698 ± 0.078	-60.70
14	BetterMap	1.727 ± 0.043	-2.77	2.179 ± 0.029	-19.23
15	ParallelismSharing	1.728 ± 0.020	0.05	2.211 ± 0.031	1.47
16	ParallelismMerging	1.725 ± 0.015	-0.13	2.218 ± 0.030	0.31
17	Graal JIT	1.697 ± 0.033	-1.66	2.178 ± 0.023	-1.80
18	Graal AOT	1.433 ± 0.002	-15.52	1.860 ± 0.001	-14.62
19	BranchyMinMax	1.415 ± 0.002	-1.31	1.820 ± 0.002	-2.15
20	Branchy08Loop	1.372 ± 0.002	-3.03	1.871 ± 0.003	2.80
21	Branchy16Loop	1.332 ± 0.002	-2.87	1.995 ± 0.002	6.64
22	CMOV	1.246 ± 0.002	-6.50	1.931 ± 0.002	-3.22
23	ILP	0.964 ± 0.002	-22.64	1.788 ± 0.001	-7.39
24	Subprocess	0.834 ± 0.001	-13.45	1.627 ± 0.003	-9.01
97	My Original	0.835 ± 0.002	0.09	1.635 ± 0.001	0.49
98	My Original + CMOV	0.836 ± 0.005	0.11	1.638 ± 0.001	0.19
99	My Original - Sharing	0.914 ± 0.020	9.48	1.709 ± 0.021	4.55
--	-	--	--	--	--
25	Bonus	0.802 ± 0.001	-	1.656 ± 0.001	-

• (*) hash function is affected, see collision table below.

MacBook Pro

• CPU: Apple M1 Pro
• MEM: 32 GB
• AFFINITY: 0-9

#	Change	Time (413)	Reduction (413)	Time (10k)	Reduction (10k)
00	Baseline	192.498 ± 2.877	0.0	188.997 ± 1.997	0.0
01	Substring	148.336 ± 1.396	-22.94	146.822 ± 0.495	-22.32
02	NoGarbage	35.499 ± 0.272	-76.07	51.339 ± 0.216	-65.03
03	DirectBuffer	31.722 ± 0.086	-10.64	48.257 ± 0.358	-6.00
04	MappedSegment	32.186 ± 0.514	1.46	55.884 ± 7.042	15.81
05	Parallelism	4.577 ± 0.647	-85.78	8.293 ± 0.568	-85.16
06	HashWhileParsing	4.418 ± 0.764	-3.48	7.414 ± 0.465	-10.61
07	SimpleMap	3.688 ± 0.106	-16.54	6.186 ± 0.686	-16.56
08	BranchyTemperature	3.328 ± 0.062	-9.76	6.620 ± 0.554	7.01
09	UnsafeParsing	2.958 ± 0.013	-11.10	4.879 ± 0.345	-26.29
10	NoKeyCopy	2.572 ± 0.014	-13.06	4.202 ± 0.028	-13.89
11	SwarStation	1.875 ± 0.025	-27.10	8.962 ± 0.039	113.30
12	SwarTemperature	2.034 ± 0.037	8.51	8.871 ± 0.029	-1.02
13	BetterHash	1.969 ± 0.048	-3.21	2.442 ± 0.017	-72.47
14	BetterMap	1.779 ± 0.032	-9.65	2.067 ± 0.018	-15.36
15	ParallelismSharing	1.841 ± 0.034	3.47	2.133 ± 0.024	3.20
16	ParallelismMerging	1.821 ± 0.015	-1.06	2.147 ± 0.020	0.65
17	Graal JIT	1.787 ± 0.013	-1.91	2.062 ± 0.060	-3.97
18	Graal AOT	1.613 ± 0.013	-9.70	1.887 ± 0.032	-8.48
19	BranchyMinMax	1.598 ± 0.007	-0.93	1.892 ± 0.029	0.26
20	Branchy08Loop	1.562 ± 0.007	-2.25	1.860 ± 0.009	-1.70
21	Branchy16Loop	1.571 ± 0.009	0.57	2.104 ± 0.016	13.12
22	CMOV	1.434 ± 0.013	-8.75	1.964 ± 0.017	-6.66
23	ILP	0.893 ± 0.003	-37.72	1.582 ± 0.015	-19.42
24	Subprocess	0.876 ± 0.005	-1.89	1.557 ± 0.015	-1.58
97	My Original	0.962 ± 0.017	9.80	1.612 ± 0.006	3.51
98	My Original + CMOV	0.854 ± 0.004	-11.26	1.531 ± 0.014	-5.03
99	My Original - Sharing	0.961 ± 0.009	-0.07	1.638 ± 0.013	1.59
--	-	--	--	--	--
25	Bonus	0.776 ± 0.004	-	1.494 ± 0.004	-

• (*) hash function is affected, see collision table below.

Collisions

The table shows the number of collisions when a certain change affected hash function.

#	Change	Stations 413	Stations 10k
06	SimpleMap	3	~1053
11	SwarStation	8	~3745
13	BetterHash	1	~712
14	BetterMap	0	~778