1BRC--Nerd Sniping the Java Community

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#1BRC | @gunnarmorling Today’s Mission Learn About…

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#1BRC | @gunnarmorling ● Software engineer at Decodable ● Former project lead of Debezium ● kcctl 🧸, JfrUnit, ModiTect, MapStruct ● Java Champion ● 1⃣ 🐝 🏎 Gunnar Morling

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#1BRC | @gunnarmorling The Goals Learn something new Have some fun along the way Inspire others to do the same

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#1BRC | @gunnarmorling The Rules ● Java-only; Version of your choice ● No dependencies ● No caching ● 10K stations, -99.9°C - +99.9°C ● Copying allowed

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#1BRC | @gunnarmorling Evaluation Environment ● 32 core AMD EPYC™ 7502P (Zen2), 8 Cores used ● 128 GB RAM ● File on RAM disk ● Five runs, slowest and fastest discarded Image © Joe Haupt https://flic.kr/p/2mG3vWA (CC BY-SA 2.0)

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#1BRC | @gunnarmorling Baseline ⌛ 04:49.679

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Parallelization Ozzy Delaney https://flic.kr/p/pMsvzE (CC BY-SA 2.0 DEED)

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#1BRC | @gunnarmorling Parallelization ⌛ 71 sec.

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#1BRC | @gunnarmorling JEP 454 Foreign Function & Memory API https://openjdk.org/jeps/454 Introduce an API by which Java programs can interoperate with code and data outside of the Java runtime. By efficiently invoking foreign functions (i.e., code outside the JVM), and by safely accessing foreign memory (i.e., memory not managed by the JVM), the API enables Java programs to call native libraries and process native data without the brittleness and danger of JNI.

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#1BRC | @gunnarmorling Parallelization–Chunking the File We have many cores, let’s put them to use!

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#1BRC | @gunnarmorling Parallelization–Chunking the File

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Parsing jjmusgrove https://flic.kr/p/2mJbA8S (CC BY 2.0 DEED)

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#1BRC | @gunnarmorling Parsing – Byte by Byte

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#1BRC | @gunnarmorling Parsing – Byte by Byte ⌛ 20 sec.

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#1BRC | @gunnarmorling Parsing – SWAR SIMD Within a Register

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#1BRC | @gunnarmorling Parsing Branchless Programming https://en.wikipedia.org/wiki/Branch_predictor

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#1BRC | @gunnarmorling Parsing – SWAR SIMD Within a Register https://richardstartin.github.io/posts/finding-bytes

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#1BRC | @gunnarmorling Parsing – SIMD Single Instruction, Multiple Data https://speakerdeck.com/gunnarmorling/to-the-moon-and-beyond-with-java-17-apis

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Bookkeeping R. D. Barry https://flic.kr/p/P5RWWR (CC BY-SA 2.0 DEED)

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#1BRC | @gunnarmorling Custom Maps – Linear Probing

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#1BRC | @gunnarmorling Custom Maps – Hash Collisions!

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#1BRC | @gunnarmorling Further Tricks & Techniques ● GraalVM as JIT Compiler ● GraalVM native binary ● The “spawn trick” ● Unsafe ● EpsilonGC ● Super-scalar execution

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#1BRC | @gunnarmorling Parsing Perfect Hashing ● Can’t use perfect hashing for keys… but for values! ● Only 1,999 distinct values: -99.9, -99.8, ..., 0.0, ..., 99.8, 99.9

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The Results Clint Budd https://flic.kr/p/2m6F7hw (CC BY 2.0 DEED)

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#1BRC | @gunnarmorling Results

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#1BRC | @gunnarmorling Results – 32 Cores / 64 Threads

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#1BRC | @gunnarmorling Results – 10K Key Set

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#1BRC | @gunnarmorling It’s a Long Journey

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#1BRC | @gunnarmorling Should You Do Any of This? It Depends

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#1BRC | @gunnarmorling The Hardest Earned Coﬀee Mug…

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#1BRC | @gunnarmorling Lessons Learned

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#1BRC | @gunnarmorling Lessons Learned ● Precise rules, covering corner cases ● Automate, automate, automate ● Build a community ● Use dedicated hardware

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#1BRC | @gunnarmorling Lessons Learned

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#1BRC | @gunnarmorling The 1BRC Community ● TCK ● Environment ● Evaluation Scripts

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#1BRC | @gunnarmorling 1BRC Mythbusters

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#1BRC | @gunnarmorling What’s Next? ?

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#1BRC | @gunnarmorling ● Repository https://github.com/gunnarmorling/1brc/ ● Show & Tell https://github.com/gunnarmorling/1brc/ discussions/categories/show-and-tell ● The Billion Row Challenge–Step-by-step from 71s to 1.7s https://questdb.io/blog/billion-row-challenge-step-by-step/ Learn More

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#1BRC | @gunnarmorling Resources Relevant JEPs and more ● Vector API (Incubator): https://openjdk.org/jeps/469 ● Foreign Function and Memory API: https://openjdk.org/jeps/454 ● CRaC: https://openjdk.org/projects/crac/