JDK
1brc
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JDK | 1brc | |
---|---|---|
191 | 5 | |
18,393 | 60 | |
2.4% | - | |
10.0 | 7.5 | |
5 days ago | 2 months ago | |
Java | C | |
GNU General Public License v3.0 only | - |
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
There are some good ideas for this type of problem here: https://github.com/dannyvankooten/1brc
After you deal with parsing and hashes, basically you are IO limited so mmap helps. A reasonable guess is that even for the optimal CUDA implementation, because there is no compute to speak of other than a hashmap, the starting of kernels and transfer of data to the GPU would likely add a noticeable bottleneck and make the optimal CUDA code slower than this pure C code.
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The One Billion Row Challenge in Go: from 1m45s to 4s in nine solutions
c dominates every other language again...https://github.com/dannyvankooten/1brc#submitting
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The One Billion Row Challenge
You can run the bin/create-sample program from this C implementation here: https://github.com/dannyvankooten/1brc
Itโs just the city names + averages from the official repository using a normal distribution to generate 1B random rows.
What are some alternatives?
Graal - GraalVM compiles Java applications into native executables that start instantly, scale fast, and use fewer compute resources ๐
1brc - 1๏ธโฃ๐๐๏ธ The One Billion Row Challenge -- A fun exploration of how quickly 1B rows from a text file can be aggregated with Java
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.
nodejs - 1๏ธโฃ๐๐๏ธ 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.
steam-runtime - A runtime environment for Steam applications
1brc - 1BRC in .NET among fastest on Linux
OkHttp - Squareโs meticulous HTTP client for the JVM, Android, and GraalVM.
kitten - A statically typed concatenative systems programming language.
intellij-community - IntelliJ IDEA Community Edition & IntelliJ Platform
imagepipe - Image processing pipeline
Caffeine - A high performance caching library for Java
V8 - The official mirror of the V8 Git repository