The Garbage Collection Handbook

https://gchandbook.org/index.html

by andsoitis • 7 months ago

284 55 7 months ago

gchandbook.org

OptionOfT• 7 months ago

My favorite story about garbage collection: https://devblogs.microsoft.com/oldnewthing/20180228-00/?p=98...

dana321• 7 months ago

now that is what i call the ultimate in garbage collection technology

naasking• 7 months ago

I think the missile impact creates a lot more garbage spread over a wider area.

whartung• 7 months ago

They do that in other places.

As I heard the tale, on the Standard Missile, they don't recirculate the hydraulic fluid, they just spit out as the missile flies. It's a wonderful engineering solution.

pfdietz• 7 months ago

And on the Falcon 9, the hydrocarbon fuel is used as hydraulic fluid, then just dumped back into the fuel tank.

Findecanor• 7 months ago

I would call that a region-based memory allocator... Only that it has a single region, ever.

antonvs• 7 months ago

Or it's a generational garbage collector with the generation management and collection functionality omitted.

eru• 7 months ago

Well, the garbage is collected when the missile hits the target region.

amelius2• 7 months ago

Yeah if you have for example a http request, you can just collect garbage you create during that request in a single region, then throw it away when the request has been handled. This is quite standard.

Agingcoder2• 7 months ago

It’s pretty standard in many places I think - the point here is not the null gc but rather exact memory requirements being proved statically.

zipy124• 7 months ago

This is one of my favourite anecodtes to tell peers and colleagues because it's important when understanding buisness case/needs against programming. We all want to make perfect software, but it isn't always neccessary.

iainctduncan• 7 months ago

I have this, it is very well written and thorough. Highly recommend!

charcircuit3• 7 months ago

I wish the author section provided what production garbage collectors the authors worked on. There's plenty of nonintuitive things you can learn in the real world, so a book including those would be both interesting and useful.

pjmlp9• 7 months ago

See "Hard Realtime Garbage Collection in Modern Object Oriented Programming Languages", the author went on co-found Aicas, one of the few companies doing real time Java on embedded.

https://www.amazon.de/-/en/Realtime-Collection-Oriented-Prog...

https://www.aicas.com/products-services/jamaicavm/

nhatcher• 7 months ago

Great book. Previous discussion: https://news.ycombinator.com/item?id=35492307

(387 points, 166 comments)

Verdex• 7 months ago

I had Hosking as a professor. Iirc, it was an okay experience. Compilers course I believe.

When the handbook came out, I bought it because "hey, I know that guy". Ultimately, I don't think it's necessary, but having a more in depth knowledge of garbage collection and the problems in the space occasionally comes in handy.

For example, what implication do finalizers have on garbage collection design? Reading about that was kind of an eye opener.

throwaway17_17• 7 months ago

I see that there is a section (relatively short) on real time GC. But for anyone who has read the Handbook, how much emphasis is placed on GC in constrained environments. I have fought the urge to implement a 3D, modern AA game with GC just to prove it is viable outside all but the most resource poor platforms or the most AAAAA, cutting edge, every cycle counted, hyper optimized game. But I am transitioning to a slightly less focused area of responsibility at work and may have some free time to prototype and this may be how I spend my winter and spring free time.

bjourne• 7 months ago

Not much. The book mostly covers theory and not platform-specific details. The explanations on various real-time gc algorithms are very thorough though.

dafelst• 7 months ago

Unreal Engine has a GC for its internal object graph, so GC is already in use in a ton of games.

01HNNWZ0MV43FF2• 7 months ago

Wouldn't all the popular games based on Unity and written in C# count?

charcircuit3• 7 months ago

Minecraft is the best selling game of all time, uses GC, and is an indie game.

znpy• 7 months ago

Yeah but it’s a game category where is that’s viable

delusional• 7 months ago

There's a bunch of caveats to that story. At one point (in one patch I recall) they got tired of passing around 3 floats separately for x, y, and z all the time, so they did what any reasonable programmer would do and created a "coordinate" structure.

This created one of the worst performing partches of the game ever, and they had to back all the way out. They ended up just passing the separate floats around again.

My takeaway is that GC doesn't have to be slow, it just imposes a bunch of new constraints on what can be fast.

pjmlp9• 7 months ago

US navy has weapons targeting systems on some battleships implemented in Java with realtime GC, equally France has missile tracking systems, also implemented in Java with realtime GC, courtesy of PTC and Aonix.

https://www.militaryaerospace.com/defense-executive/article/...

https://www.lockheedmartin.com/en-us/products/aegis-combat-s...

https://vita.militaryembedded.com/1670-aonix-uss-bunker-hill...

Not all GC are born alike, and in real life there isn't "insert credit to continue".

indigo9453• 7 months ago

I think you would be hard-pressed to find a modern AA game that does not already use a GC. The major game engines Unreal and Unity are garbage collected - although they use manual memory management for some of their internals, the exposed API surface (including the C++ API) is designed with garbage collection in mind.

Notably, the popular-with-hobbyists Godot Engine does not use a garbage collector. It uses reference counting with some objects, but does not provide cycle detection, thus requires all objects to be laid out in a tree structure (which the engine is built around).

pjmlp9• 7 months ago

Reference counting is chapter 5 on the linked book.

pizlonator8• 7 months ago

Unreal has an incremental GC

Agingcoder2• 7 months ago

This is a truly remarkable book, and a must read for any engineer who depends on a gc . And if you don’t need a gc, the book starts by talking about allocators, which are actually very important too !

xenophonf• 7 months ago

I wish there was a big, friendly "buy now" link that would get me the print book and EPUB file. The site promotes the book. I'm not sure why they don't make buying it stupid simple.

The Garbage Collection Handbook

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