Jimfs
Disruptor
Jimfs | Disruptor | |
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5 | 30 | |
2,380 | 17,029 | |
0.3% | 0.4% | |
8.5 | 5.4 | |
about 21 hours ago | 4 months ago | |
Java | Java | |
Apache License 2.0 | Apache License 2.0 |
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Jimfs
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How to write unit tests in C++ relying on non-code files?
Java has in-memory file systems that are essentially geared for this exact use case, eg jimfs[0]. You create your filesystem and any files you need when your tests are starting up, and your classes talk to them rather than the “real” ones. Maybe a similar project exists for the C++ ecosystem?
[0] https://github.com/google/jimfs
- An in-memory file system for Java
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Any library you would like to recommend to others as it helps you a lot? For me, mapstruct is one of them. Hopefully I would hear some other nice libraries I never try.
Recently been using JIMFS. Made my tests much faster and cleaner!
- An in memory file system
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Working and unit testing with temporary files in Java
I use Google's JIMFS "Just In Memory Filesystem" https://github.com/google/jimfs in my unit tests and have been very happy. No need to clean something up that disappears as soon as the test is over. Let's you create unix or windows style filesystems and I've used it to test a disk space healthcheck because you can set a limit to the size of the filesystem it creates. Very flexible and easy to use.
Disruptor
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Gnet is the fastest networking framework in Go
https://lmax-exchange.github.io/disruptor/#_what_is_the_disr.... Unfortunately IIUC writing this in Go still prevents the spin-locked acceptor thread from achieving the kind of performance you could get in a non-GC language, unless you chose to disable GC, so I'd guess Envoy is still faster.
https://gnet.host/docs/quickstart/ it's nice that you can use this simply though. Envoy is kind of tricky to setup with custom filters, so most of the time it's just a standalone binary.
[0] https://blog.envoyproxy.io/envoy-threading-model-a8d44b92231...
[1] https://lmax-exchange.github.io/disruptor/#_what_is_the_disr...
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A lock-free ring-buffer with contiguous reservations (2019)
See also the Java LMAX Disruptor https://github.com/LMAX-Exchange/disruptor
I've built a similar lock-free ring buffer in C++11 https://github.com/posterior/loom/blob/master/doc/adapting.m...
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JEP Draft: Deprecate Memory-Access Methods in Sun.misc.Unsafe for Removal
"Why we chose Java for our High-Frequency Trading application"
https://medium.com/@jadsarmo/why-we-chose-java-for-our-high-...
LMAX Disruptor customers
https://lmax-exchange.github.io/disruptor/
Among many other examples.
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LMAX Disruptor – High Performance Inter-Thread Messaging Library
Current documentation
https://lmax-exchange.github.io/disruptor/
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Progress on No-GIL CPython
LMAX Disruptor has on their wiki that average latency to send a message from one thread to another at 53 nanoseconds. For comparison a mutex is like 25 nanoseconds and more if Contended but a mutex is point to point synchronization.
The great thing about it is that multiple threads can receive the same message without much more effort.
https://github.com/LMAX-Exchange/disruptor/wiki/Performance-...
https://gist.github.com/rmacy/2879257
I am dreaming of language that is similar to Smalltalk that stays single threaded until it makes sense to parallise.
I am looking for problems to parallelism that are not big data. Parallelism is like adding more cars to the road rather than increasing the speed of the car. But what does a desktop or mobile user need to do locally that could take advantage of the mathematical power of a computer? I'm still searching.
- Disruptor 4.0.0 Released
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Anything can be a message queue if you use it wrongly enough
Database config should be two connection strings, 1 for the admin user that creates the tables and anther for the queue user. Everything else should be stored in the database itself. Each queue should be in its own set of tables. Large blobs may or may not be referenced to an external file.
Shouldn't a message send be worst case a CAS. It really seems like all the work around garbage collection would have some use for in-memory high speed queues.
Are you familiar with the LMAX Disruptor? Is is a Java based cross thread messaging library used for day trading applications.
https://lmax-exchange.github.io/disruptor/
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Any library you would like to recommend to others as it helps you a lot? For me, mapstruct is one of them. Hopefully I would hear some other nice libraries I never try.
Disruptor for inter-thread messaging
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Measuring how much Rust's bounds checking actually costs
I have never worked in any industries where a perf margin was that small. It is funny, in HFT there are folks using Lmax (Java) and then you have folks writing their own TCP/IP stacks on FPGAs to do trading.
What are some alternatives?
Modern Java - A Guide to Java 8 - Modern Java - A Guide to Java 8
JCTools
Lanterna - Java library for creating text-based GUIs
Agrona - High Performance data structures and utility methods for Java
OpenRefine - OpenRefine is a free, open source power tool for working with messy data and improving it
fastutil - fastutil extends the Java™ Collections Framework by providing type-specific maps, sets, lists and queues.
Joda-Money - Java library to represent monetary amounts.
MPMCQueue.h - A bounded multi-producer multi-consumer concurrent queue written in C++11
LightAdmin - [PoC] Pluggable CRUD UI library for Java web applications
Eclipse Collections - Eclipse Collections is a collections framework for Java with optimized data structures and a rich, functional and fluent API.
Codename One - Cross-platform framework for building truly native mobile apps with Java or Kotlin. Write Once Run Anywhere support for iOS, Android, Desktop & Web.
Javolution