compiler VS multiversion-concurrency-contro

Wow! Thank you for your hard work. I use python for all experimental work so this would speed up my scripting work, such as processing data from API calls or filesystem.

I wrote a simple toy JIT for a Javascript-like language. It might be useful for others to learn from because it's so simply written and not complicated. I do lazy patching of callsites, I haven't got anywhere near as advanced as tracing or copy-and-patching. Much of the code I wrote for this JIT was written in Python and ported to C. The Java Virtual Machine has a template interpreter which is interesting to research.

I haven't got around to encoding amd64 x86_64 instructions as bitmasks yet, so I've hardcoded it.

[1]: https://github.com/samsquire/compiler

Thank you for this article.

I'm a beginner to programming language implementation and design but here's what I learned. But what I want to do this with this comment I want to encourage you to start work on your programming language and just "Do Something©", Anything! You might have always dreamed to create a programming language. You can indeed try that! Have faith that you can do something, even if it's simple or incomplete, at least you learned something and got another skill.

I don't want to be trapped by the idea that building your own programming language is impossibly difficult and that it will never be used so what's the point.

It's so worthwhile.

You can still do something! Effort doesn't have to be wasted! Go and try write a simple virtual machine: it's just a for loop over instructions that manipulate memory. I wrote a non-bytecode compiler, which just uses List for instructions and HashMap for instruction arguments.

Andrew Kling built a browser and operating system and Terry Davis built an operating system. They encourage that someone can in fact learn a lot and do a lot.

I don't want to endlessy design things OR only write implementations. I think you can write lots of ideas down AND spend time implementing things and getting your keyboard busy.

I wrote this incomplete JIT compiler in C which has a simple nondesigned frontend that resembles Javascript. ANF is my intermediate representation.

https://github.com/samsquire/compiler

I wrote a multithreaded imaginary assembly language that sends integers between threads through mailboxes but nowhere near LMAX Disruptor performance.

I think you should avoid spending too much time on your parser or lexer, use the Kaledeiscope LLVM tutorial to learn how to write recursive descent parsers and move onto code generation. I did mine with switch statements. The more you actually write parsers the easier it gets, but at first when you have no clue, you CAN just read someone else's implementation of it. Understand it, then write your own to your own design. if you get Analysis paralysis and worry about making a mistake or unoptimal decision and that prevents you from doing something suboptimal but actually do something.

I rushed through my compiler to get to the code generation step because my goal was code generation.

My dream: parallel and concurrent language that combines threads and coroutines with efficient interthread communication similar to LMAX Disruptor and allows writing of efficient pipelines that are serialisable like Temporal.io.

Thanks for this.

I started a basic toy JIT compiler for a language that looks similar to JavaScript. It is incomplete.

https://github.com/samsquire/compiler

With these kinds of projects there is a lot of work to be done and I feel it's difficult to get started reading a codebase for a JIT compiler or gcc or LLVM.

https://github.com/samsquire/compiler

It's a toy and incomplete but I've worked on compiling MOV and ADD instructions.

On thing you can do it implement a JIT compiler.

Here's Martin Jacob's code to execute arbitrary memory:

https://gist.github.com/martinjacobd/3ee56f3c7b7ce621034ec3e...

Since your C program is already in memory, you have access to the C standard library and don't have to worry about linking or object formats :-) but you'll have to worry about parameter passing and FFI.

My JIT compiler based on this idea is here https://github.com/samsquire/compiler but it is incomplete.

This is interesting, thank you.

I really should learn from BEAM and the OTP and learn Erlang. I get the feeling it's super robust and reliable and low maintenance. I wrote a userspace multithreaded scheduler which distributes N lightweight threads to M kernel threads.

https://github.com/samsquire/preemptible-thread

I recently wrote a JIT compiler and got lazy compilation of machine code working and I'm nowhere near beginning optimisation

https://github.com/samsquire/compiler

How do you write robust software, that doesn't crash when something unexpected goes on?

I looked at sozo https://github.com/sozu-proxy/sozu

and I'm thinking how to create something that just stays up and running regardless.

https://github.com/samsquire/multiversion-concurrency-contro...

And I implemented a 3 way text diff with myers algorithm based on https://blog.jcoglan.com/2017/02/12/the-myers-diff-algorithm...

https://github.com/samsquire/text-diff

I implemented an eventually consistent mesh protocol that uses timestamps to provide last write wins

I think I lean towards per-thread sharding instead of mutex based or lock free data structures except for lockfree ringbuffers.

You can get embarassingly parallel performance if you split your data by thread and aggregate periodically.

If you need a consistent view of your entire set of data, that is slow path with sharding.

In my experiments with multithreaded software I simulate a bank where many bankaccounts are randomly withdrawn from and deposited to. https://github.com/samsquire/multiversion-concurrency-contro...

I get 700 million requests per second due to the sharding of money over accounts.

If you want some sample code to implement MVCC, I implemented MVCC in multithreaded Java as a toy example

https://github.com/samsquire/multiversion-concurrency-contro...

First read TransactionC.java then read MVCC.java

I wrote an unrolled switch statement in Java to simulate eager async/await across treads.

https://github.com/samsquire/multiversion-concurrency-contro...

The goal is that a compiler should generate this for you. This code is equivalent to the following:

   task1:

https://doc.rust-lang.org/book/ch16-00-concurrency.html

I've been working on implementing Java async/await state machine with switch statements and a scheduling loop. If the user doesn't await the async task handle, then the task's returnvalue is never handled. This is similar to the Go problem with the go statement.

https://github.com/samsquire/multiversion-concurrency-contro...

If your async call returns a handle and

yield value2++

https://github.com/samsquire/multiversion-concurrency-contro...

I am still working on allowing multiple coroutines to be in flight in parallel at the same time. At the moment the tasks share the same background thread.

I asked this stackoverflow question regarding C++ coroutines, as I wanted to use coroutines with a thread pool.

https://stackoverflow.com/questions/74520133/how-can-i-pass-...

This is very interesting. Thank you for submitting this and thank you for working on this.

I am highly interested in parallelism and high concurrency. I implemented multiversion concurrency control in Java.

https://github.com/samsquire/multiversion-concurrency-contro...

I am curious how to handle replication with high concurrency. I'm not sure how you detect dangerous reads+writes to the same key (tuples/fields) across different replica machines. In other words, multiple master.

I am aware Google uses truetime and some form of timestamp ordering and detection of interfering timestamps. But I'm not sure how to replicate that.

I began working on an algorithm to synchronize database records, do a sort, then a hash for each row where hash(row) = hash(previous_row.hash + row.data)

Then do a binary search on hashes matching/not matching. This is a synchronization algorithm I'm designing that requires minimal data transfer but multiple round trips.

The binary search would check the end of the data set for hash(replica_a.row[last]) == hash(replica_b.row[last]) then split the hash list in half and check the middle item, this shall tell you which row and which columns are different.

https://github.com/samsquire/multiversion-concurrency-contro...

I want to redesign the architecture of the async/await to be easier to understand. I want to use a state machine somehow.

I wrote an unrolled state machine for my async/await in Java. This models a simple async/await program and runs tasks on other threads - without locks. I use a design I call token ring parallelism, where threads take turns and are linked together in a ring structure.

https://github.com/samsquire/multiversion-concurrency-contro...

I wrote a own lock free algorithm here that I use to do message passing between actor threads. My goal is high throughput performance and low latency.

https://github.com/samsquire/multiversion-concurrency-contro...

With 11 threads (on a 12 core processor, deliberately left one core for Windows)

I then started writing a parser for a high level language and then code generation from the AST to the imaginary assembly. My interpreter is multithreaded and can send integers between interpreters. It is very early and doesn't do much.

Code is at https://github.com/samsquire/multiversion-concurrency-contro...

The high level language looks similar to Javascript except I tried to parse everything as an expression. I need to parse functions as expressions.

I was experimenting with Protothreads in C recently to try understand how it worked and I wrote a giant switch statement and a while loop in Java to simulate async/await. It would be interesting to do codegen for coroutines.

here's that giant switch statement and scheduler https://github.com/samsquire/multiversion-concurrency-contro...

One idea for a stackless design I had was to preallocate memory for each method call for a call to that function and avoid a stack altogether. This would allow coroutines between methods and avoid the function colour problem because everything is a coroutine.

Is there any communities for programming language developers? Where do all the language developers meet up and talk theory and implementation? I am on eatonphil's discord and we talk there.

One problem I am trying to understand how to solve is how you would write a multithreaded interpreter and language that allowed parallel interpretation similar to C# and Java. If the allocator is thread safe and you share an object pool between interpreters and you hash object equality by sourcecode, then you could send objects between threads with only a synchronization cost.

I believe Python has the problem that object identity is different in each subinterpreter so you need to marshall the data.