JDK
1brc
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JDK | 1brc | |
---|---|---|
191 | 28 | |
18,393 | 5,077 | |
2.4% | - | |
10.0 | 9.9 | |
5 days ago | 20 days ago | |
Java | Java | |
GNU General Public License v3.0 only | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
JDK
- JEP draft: Exception handling in switch
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Java 23: The New Features Are Officially Announced
Completely gutted from the OpenJDK, last I checked. See here for the culprit PR: https://github.com/openjdk/jdk/pull/18688
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macOS 14.4 might break Java on your machine
> Yes, they're changing one aspect of signal handler use to work around this problem. They're not stopping the use of signal handlers in general. Hotspot continues to use signals for efficiency in general. See https://github.com/openjdk/jdk/blob/9059727df135dc90311bd476...
This whole thread is about SIGSEGV, and specifically their SIGSEGV handling. However, catching normal signals is not about efficiency.
Some of their exception handling is still odd: There is no reason for a program that receives SIGILL to ever attempt continuing. But others is fine, like catching SIGFPE to just forward an exception to the calling code.
(Sure, you could construct an argument to say that this is for efficiency if you considered the alternative to be implementing floating point in software so that all exceptions exist in user-space, but hardware floating point is the norm and such alternative would be wholly unreasonable.)
> The wonderful thing about choosing not to care about facts is having whatever opinions you want.
I appreciate the irony of you making such statement, proudly thinking that your opinion equals fact, and therefore any other opinion is not.
This discussion is nothing but subjective opinion vs. subjective opinion. Facts are (hopefully, as I can only speak for myself) inputs to both our opinions, but no opinion about "good" or "bad", "nasty" or not can ever be objective. Objective code quality does not exist.
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The Return of the Frame Pointers
I remember talking to Brendan about the PreserveFramePointer patch during my first months at Netflix in 2015. As of JDK 21, unfortunately it is no longer a general purpose solution for the JVM, because it prevents a fast path being taken for stack thawing for virtual threads: https://github.com/openjdk/jdk/blob/d32ce65781c1d7815a69ceac...
- JDK-8180450: secondary_super_cache does not scale well
- The One Billion Row Challenge
- AVX2 intrinsics for Arrays.sort methods (int, float arrays)
- A gentle introduction to two's complement
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Java JEP 461: Stream Gatherers
Map doesn't implement the Collection interface.
https://github.com/openjdk/jdk/blob/master/src/java.base/sha...
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C++23: Removing garbage collection support
C++ lets you write anything you can imagine, and the language features and standard library often facilitate that. The committee espouses the view that they want to provide many "zero [runtime] cost," abstractions. Anybody can contribute to the language, although the committee process is often slow and can be political, each release the surface area and capability of the language gets larger.
I believe Hazard Pointers are slated for C++26, and these will add a form "free later, but not quite garbage collection" to the language. There was a talk this year about using hazard pointers to implement a much faster std::shared_ptr.
It's a language with incredible depth because so many different paradigms have been implemented in it, but also has many pitfalls for new and old users because there are many different ways of solving the same problem.
I feel that in C++, more than any other language, you need to know the actual implementation under the hood to use it effectively. This means knowing not just what the language specifies, but can occaissionally require knowing what GCC or Clang generate on your particular hardware.
Many garbage collected languages are written in or have parts of their implementations in C++. See JS (https://github.com/v8/v8)and Java GC (https://github.com/openjdk/jdk/tree/36de19d4622e38b6c00644b0...)
I am not an expert on Java (or C++), so if someone knows better or can add more please correct me.
1brc
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The One Billion Row Challenge in CUDA: from 17 minutes to 17 seconds
This would be the code to beat. Ideally with only 8 cores but any number of cores is also very interesting.
https://github.com/gunnarmorling/1brc/discussions/710
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One Billion Row Challenge in Golang - From 95s to 1.96s
Given that 1-billion-line-file is approximately 13GB, instead of providing a fixed database, the official repository offers a script to generate synthetic data with random readings. Just follow the instructions to create your own database.
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1BRC Merykitty's Magic SWAR: 8 Lines of Code Explained in 3k Words
Local disk I/O is no longer the bottleneck on modern systems: https://benhoyt.com/writings/io-is-no-longer-the-bottleneck/
In addition, the official 1BRC explicitly evaluated results on a RAM disk to avoid I/O speed entirely: https://github.com/gunnarmorling/1brc?tab=readme-ov-file#eva... "Programs are run from a RAM disk (i.o. the IO overhead for loading the file from disk is not relevant)"
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Processing One Billion Rows in PHP!
You may have heard of the "The One Billion Row Challenge" (1brc) and in case you don't, go checkout Gunnar Morlings's 1brc repo.
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The One Billion Row Challenge in Go: from 1m45s to 4s in nine solutions
Here’s a thread on results with duckdb, I don’t mean to discourage you taking a shot at all though: https://github.com/gunnarmorling/1brc/discussions/39
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Ask HN: How can I learn about performance optimization?
If you are in “javaland” look at billion row challenge, you will learn a lot - https://github.com/gunnarmorling/1brc
- Lessons Learned from Doing the One Billion Row Challenge
- 1B Row Challenge Shows Java Can Process 1B Rows File in 2 Seconds
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From slow to SIMD: A Go optimization story
Even manual vectorization is pain...writing ASM, really?
Rust has unstable portable SIMD and a few third-party crates, C++ has that as well, C# has stable portable SIMD and a very small BLAS-like library on top of it (hell it even exercises PackedSIMD when ran in a browser) and Java is getting stable Panama vectors some time in the future (though the question of codegen quality stands open given planned changes to unsafe API).
Go among these is uniquely disadvantaged. And if that's not enough, you may want to visit 1Brc's challenge discussions and see that Go struggles get anywhere close to 2s mark with both C# and C++ are blazing past it:
https://hotforknowledge.com/2024/01/13/1brc-in-dotnet-among-...
https://github.com/gunnarmorling/1brc/discussions/67
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JEP Draft: Deprecate Memory-Access Methods in Sun.misc.Unsafe for Removal
In terms of performance: I realize that this is a somewhat "toy" issue, and it's a sample size of 1, but for the currently ongoing "One Billion Row Challenge"[1] (an ongoing Java performance competition related to parsing and aggregating a 13 GB file), all of the current top-performers are using Unsafe. More specifically, the use of Unsafe appears to have been the change for a few entries that allowed getting below the 3-second barrier in the test.
1. https://github.com/gunnarmorling/1brc
What are some alternatives?
Graal - GraalVM compiles Java applications into native executables that start instantly, scale fast, and use fewer compute resources 🚀
1brc - C99 implementation of the 1 Billion Rows Challenge. 1️⃣🐝🏎️ Runs in ~1.6 seconds on my not-so-fast laptop CPU w/ 16GB RAM.
aircraft - The A32NX & A380X Project are community driven open source projects to create free Airbus aircraft in Microsoft Flight Simulator that are as close to reality as possible.
yolov7-object-tracking - YOLOv7 Object Tracking Using PyTorch, OpenCV and Sort Tracking
steam-runtime - A runtime environment for Steam applications
nodejs - 1️⃣🐝🏎️ The One Billion Row Challenge with Node.js -- A fun exploration of how quickly 1B rows from a text file can be aggregated with different languages.
OkHttp - Square’s meticulous HTTP client for the JVM, Android, and GraalVM.
csvlens - Command line csv viewer
kitten - A statically typed concatenative systems programming language.
pocketbase - Open Source realtime backend in 1 file
intellij-community - IntelliJ IDEA Community Edition & IntelliJ Platform
Apache Arrow - Apache Arrow is a multi-language toolbox for accelerated data interchange and in-memory processing