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Posted by gkfasdfasdf 4 hours ago

Jemalloc 5.4.0(github.com)
108 points | 27 comments
vocx2tx 2 hours ago|
For some context on why this release is notable: Jemalloc Postmortem [0]

[0] https://news.ycombinator.com/item?id=44264958

lordnacho 1 hour ago||
I always wondered, is it French? "Je m'alloc du memory"
sam_lowry_ 53 minutes ago||
Rather a tradition to call a malloc by the initials of the implementer: Jason Evans malloc (jemalloc), Poul-Henning Kamp malloc (phkmalloc), Doug Lea (dlmalloc).

P.S. I also wondered whether systemd had any cultural reference to Système D aka Système Débrouillard, but Pottering does not seem to be someone engaging in word play, so probably not.

tefkah 21 minutes ago||
damn i always thought it was a french thing, this is blowing my mind
simonask 40 minutes ago||
Thanks, now my brain will forever read it like that. I'm not even a little bit French.
ksec 45 minutes ago||
Ok. Why both the homepage and its Github repo doesn't make a single mention of Jason Evans? I know he stepped down but surely it is at least worst mentioning it?

Is Meta still using it and developing it? If not who are the driving force behind it now? I just checked there wasn't a release since 2022 and then we have this now. Something changed?

Just wish we have a little bit of context. But it is also great it is continue being maintained. It makes a huge difference for Ruby on Rails Apps.

feldrim 11 minutes ago||
It's only mentioned in history: https://github.com/jemalloc/jemalloc/wiki/Background#history
aktenlage 35 minutes ago||
> Just wish we have a little bit of context

See the comment of vocx2tx

skavi 13 minutes ago||
does anyone familiar with the art have thoughts on why only tcmalloc switched from thread caches to cpu caches? would it make linux behavior diverge too much from other platforms?
ZenoArrow 2 hours ago|
Why is this on the HN front page? Is there something particularly noteworthy about this release?
imhoguy 1 hour ago||
I upvoted it because I benefit from jemalloc in my stack (RoR) and I am tired of AI taking over HN front page. Let the hacker spirit be back!
adityapatadia 17 minutes ago|||
Upvoted for the same reason. We would not be able to run our workloads without Jemalloc. Kudos to this awesome piece of software.
smartmic 5 minutes ago|||
You are not alone - my first thought was 'oh, HN is trying to bring back the disappointed hackers'. All this AI hype over every little model update fart is so exhausting and boring …
aktenlage 2 hours ago|||
They resumed development on jemalloc only recently, after years of no releases.
charcircuit 28 minutes ago||
Development was never stopped for jemalloc. This is a common misconception. There just were not releases being tagged and packaged against the ongoing development.
defrost 2 hours ago|||
The noted resumption and likely a small amount of halo effect from the Comparison of Malloc() Algorithms thread two / three days ago.

- https://news.ycombinator.com/item?id=49715318

ck45 2 hours ago|||
I just checked whether it's the first release after Jason Evans stepped down as maintainer, but it isn't. That was the previous release, 5.3.1
gjvc 3 minutes ago|||
[delayed]
baq 1 hour ago||
jemalloc is something you should be aware of if you do software for a living
stackghost 1 hour ago|||
In the Before Times, the vast majority of software was written in garbage collected language where a working knowledge of the relative merits of C memory allocators is not useful or particularly relevant.

Why would the scads of people writing JavaScript, Java, python, go, rails, etc need to be aware of jemalloc?

xxs 16 minutes ago|||
>...the vast majority of software was written in garbage collected language

and even then recently it costed (us) quite a few months to blame JVM and later the default glibc memory allocator for running out native (java heap memory) - had to exclude all possible native libs, direct buffers, sockets, thread stacks and so on. Changing the malloc to jemalloc solved the issue, even though initially it was done for its debugging capabilities.

It's just a great memory allocator.

iam-da-author 50 minutes ago|||
TL;DR: Because the runtime of most GC:d languages uses malloc for its internal data structures.

I work for the runtime team of JPG @ Oracle. We use malloc in Hotspot, quite a lot actually! Providing your JVM with a good malloc can improve the performance of the runtime, both in terms of CPU and memory, by quite a bit.

I don't think you need the details, but it's good to be aware that some mallocs are better than others, and there are multiple of them. Being aware of jemalloc is a good way of being aware of the facts I just mentioned :-).

rfgplk 1 hour ago|||
Why? Writing a memory allocator is quite simple, and I'd argue that _everyone_ should write one from scratch for any kind of high performance application. It's also trivial to outperform general purpose allocators that have to satisfy countless constraints. I've written numerous special purpose mallocs that are a) both provably (formally) safer than the standard armada and b) significantly faster (>10x throughput).
groomlake 1 hour ago|||
Your experience writing memory allocators is irrelevant. The point is that jemalloc is widely used and that’s why it makes sense to be aware of it.
stackghost 1 hour ago||||
Writing an allocator is simple, you’re correct, but writing an allocator that doesn’t suck is not simple.
HackerThemAll 1 hour ago|||
I'd happily see performance, latency and stability of your allocators in massively multithreaded, long-living programs with workloads where hundreds or thousands of parallel threads continuously create and destroy short-lived small and medium objects.

Writing allocators for domain-specific access patterns is easy. Writing a general-purpose high performing, stable allocator with bounded P99 latency is hard.

Give your friend, Dunning–Kruger, some better pills to keep him from speaking through you.

Pannoniae 1 hour ago|||
You're correct, but his point is that you don't need to solve the generic problem. Solving the generic problem is very hard. Grug doesn't like solving hard problem. What does grug do? Solve five easy problems. Make an arena for the short-lived objects, reuse the objects, use generic multithreaded malloc for the rest. Grug happy.
matheusmoreira 47 minutes ago|||
Not everything needs to be general purpose. Allocation can be as easy as bumping a pointer, and it's hard to beat that.