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Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

gossamer-lang.org

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Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#21

Post by quotemstr »

adastra22 wrote: post #15
quotemstr wrote: post #8

Earlier quoted context omitted.

ZGC is extremely good work. https://wiki.openjdk.org/spaces/zgc/pages/34668579/Main > ZGC performs all expensive work concurrently, without stopping the execution of application threads for more than a millisecond. It is suitable for applications which require low latency. Pause times are independent of the heap size that is being used. ZGC works well with heap sizes from a few hundred megabytes to 16TB. Go's GC is a…

A millisecond is an eternity. It is 1/3 of the entire time allocated to a frame update in a modern game.

Various GCs can go faster now too. JEP 376 talks about hundreds-of-microsecond work done in pause now that GC no longer has to scan the whole stack.

That said: 1ms? 1ms is getting into the sorts of latency the OS and hardware impose on your program no matter what it does. For example, on x86, a SMI can take 300us, or 1000us if you're unlucky. I've seen softirqs for shitty wifi chips take a hundred milliseconds! And God help you if you take a hard page fault:

You're worried about 1ms latencies, right? So you're mlock()ing all memory? Running RT threads pinned to cores? Carefully using PI and static priorities to avoid inversions? Avoiding blocking IO everywhere, not even for graphics page-flipping? Managing thermal headroom to avoid involuntary clock collapses? And it should go without saying, but I have to ask: you're running a PREEMPT_RT kernel, right?

No? You're not doing any of these things? Then why are you worried about 1ms in GC?

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#22

Post by lstodd »

IDK what's the fuss. m:n scheduled by io is .. 2000s-era. The implementation was so obvious in like 2005, that even I patched then Python 2.6 in, so we at my then company could get rid of Twisted.

Also let you remind that M:N scheduling was the FreeBSD's pthread implementation for quite a bit too long. No, it didn't play well with MySQL at the time.

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#23

Post by gomoboo »

platinumrad wrote: post #3
quotemstr wrote: post #2

Gossamer has a cycle collector and eager reference counting. Good luck dropping the last reference to a 10,000-node graph, especially if cyclic. That means it doesn't have "pause free" memory. If you want pause freedom, go use ZGC or another modern GC on a modern VM. I just can't take seriously this spate of languages that ignore the past 30 years of research into automatic memory management. We have multiple open-so…

> We have multiple open-source pauseleses miracles right there before our eyes Is this meaningfully true in a practical sense? I've been writing code with soft real-time requirements and I don't think your notion of "pauseless" suffices. And if these miracles are open-source and right before our eyes, why do languages like Crystal and D still use Boehm?

D uses a homegrown GC not Boehm: - https://dlang.org/spec/garbage.html - https://dlang.org/blog/2017/03/20/dont-fear-the-reaper/

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#24

Post by Balinares »

kccqzy wrote: post #20
samuell wrote: post #12

Glad to see more languages adopt true goroutines [edit: lightweight threads or fibers] with M:N scheduling. Surprised more haven't. Among compiled language I'm only aware of Go and Crystal off the top of my mind.

Haskell does too. And it predates Go by a large margin, such that calling it goroutine is weird. And within Google, the C++ implementation fiber also predated goroutines. It really shows that this is more of a library feature rather than a language feature.

In fairness, goroutine is far catchier than >>=.

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#25

Post by treyd »

adastra22 wrote: post #15
quotemstr wrote: post #8

Earlier quoted context omitted.

ZGC is extremely good work. https://wiki.openjdk.org/spaces/zgc/pages/34668579/Main > ZGC performs all expensive work concurrently, without stopping the execution of application threads for more than a millisecond. It is suitable for applications which require low latency. Pause times are independent of the heap size that is being used. ZGC works well with heap sizes from a few hundred megabytes to 16TB. Go's GC is a…

A millisecond is an eternity. It is 1/3 of the entire time allocated to a frame update in a modern game.

Game GCs are interesting because you know that the execution is structured like this and you know how much time you have left before you have to switch back to application code for the next frame/time step. There's interesting optimizations you can make around this and could almost completely avoid user-observable GC pauses.

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#26

Post by Zak »

throwrioawfo wrote: post #7

There was once a time when I'd see a page like this and think "wow, must be a great project with such a polished website". Now, it's just a neutral or perhaps even very slightly negative signal (especially the em-dash in the very first line of the page). Anyone able to tell me if this is a project actually worth paying attention to, or just another raindrop in the current monsoon of slop?

A card grid with rounded corners as the second section and a dark blue or purple theme just scream "designed by Claude".

It's decent design, but not a useful quality signal.

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#27

Post by lstodd »

quotemstr wrote: post #14
platinumrad wrote: post #10

Earlier quoted context omitted.

You seem to have a very low opinion of other people. If these miraculous collectors are so generally applicable, why are very smart people putting effort into things like Perseus?

Smart, honest people can have sincere and earnest disagreements. I believe the manual-memory-management people are mistaken. That's not to say they're stupid: it means I believe they're going down the wrong path, as smart people have done since time immemorial. I wish them all the best. That said, I must wonder what other innovations they reject if they insist that GC is unacceptable.

We insist that GC is unacceptable only because we insist that uncontrollable latency is unacceptable.

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#28

Post by LoganDark »

lstodd wrote: post #27
quotemstr wrote: post #14

Earlier quoted context omitted.

Smart, honest people can have sincere and earnest disagreements. I believe the manual-memory-management people are mistaken. That's not to say they're stupid: it means I believe they're going down the wrong path, as smart people have done since time immemorial. I wish them all the best. That said, I must wonder what other innovations they reject if they insist that GC is unacceptable.

We insist that GC is unacceptable only because we insist that uncontrollable latency is unacceptable.

The entire concept of a pauseless GC is that you have no uncontrollable latency. The GC can run on a background thread with zero stop-the-world.

Of course, this assumes you're in a preemptive environment with access to other threads, etc.

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#29

Post by kelseyfrog »

adastra22 wrote: post #15
quotemstr wrote: post #8

Earlier quoted context omitted.

ZGC is extremely good work. https://wiki.openjdk.org/spaces/zgc/pages/34668579/Main > ZGC performs all expensive work concurrently, without stopping the execution of application threads for more than a millisecond. It is suitable for applications which require low latency. Pause times are independent of the heap size that is being used. ZGC works well with heap sizes from a few hundred megabytes to 16TB. Go's GC is a…

A millisecond is an eternity. It is 1/3 of the entire time allocated to a frame update in a modern game.

Exactly. This is why Minecraft Java edition was such a disastrous flop.

Re: Gossamer: a Rust-flavoured language with real goroutines and pause-free memory

#30

Post by felixgallo »

throwrioawfo wrote: post #7

There was once a time when I'd see a page like this and think "wow, must be a great project with such a polished website". Now, it's just a neutral or perhaps even very slightly negative signal (especially the em-dash in the very first line of the page). Anyone able to tell me if this is a project actually worth paying attention to, or just another raindrop in the current monsoon of slop?

you know what's even worse than slop? Zero-effort 'is this maybe slop can someone tell me' posting.
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