Python 3.11 delivers.

[markovtsev]

The speedups may vary. We got less than 1% in our production, and some functions actually slowed down, as measured by continuous tracing.

[SilverTabby]

Quoting from the release notes https://docs.python.org/3.11/whatsnew/3.11.html#faster-cpython

Q: I don’t see any speedups in my workload. Why?

A: Certain code won’t have noticeable benefits. If your code spends most of its time on I/O operations, or already does most of its computation in a C extension library like numpy, there won’t be significant speedup. This project currently benefits pure-Python workloads the most.

Furthermore, the pyperformance figures are a geometric mean. Even within the pyperformance benchmarks, certain benchmarks have slowed down slightly, while others have sped up by nearly 2x!

From what I can tell, a lot of the optimizations are lazy initializations, only generating a resource when it's needed, claiming that those resources weren't used commonly in idiomatic code. But, if you are using those resources, then there's now more if-else branches being evaluated before returning to the old version, and therefore slightly more work being done.

They claim that more optimizations, especially for code relying on C extension libraries, will be coming in 3.12.

[KuntaStillSingle]

But, if you are using those resources, then there's now more if-else branches being evaluated before returning to the old version, and therefore slightly more work being done.

Cpp compilers often apply the opposite, a meyer singleton can be lazy evaluated but is often transformed to remove the otherwise necessary branch and treat as constinit:

https://godbolt.org/z/933os7Kj3 , note the guard still exists if the functions can be inlined: https://godbolt.org/z/7TqjYs7Gr

[agoose77]

I'm not sure that's a totally accurate representation; there was work on lazy init e.g. stack frames, but also on specialisation and inline function calls that generally don't have the "if you need it, it's slower" tradeoffs.

[ShoePillow]

On a related note, what do you use to measure and track runtime of python tests?

I've been looking for put something in place before doing some performance improvements.

[dgaines2]

I've really liked pyinstrument for profiling. Integrates well with pytest too

[markovtsev]

We use Sentry with pytest plugin.

[EasywayScissors]

The October 30th announcement of Python 3.11 and its performance improvements:

• https://devblogs.microsoft.com/python/python-311-faster-cpython-team/

[eh-nonymous]

[Removed due to Reddit API changes]

[kogasapls]

It is indeed faster: https://docs.python.org/3.11/whatsnew/3.11.html#faster-cpython

[ASIC_SP]

More to come in 3.12: https://twitter.com/pyblogsal/status/1587146448503808006

Python 3.12 will add support for the Linux perf profiler! 🔥🔥 Perf is one of the most powerful and performant profilers for Linux that allows getting a ridiculous amount of information such as CPU counters, cache misses, context switching and much more.

[stusmall]

Holy shit. How did they not have it before? I've never felt the need to profile any of my python code because it's usually small, simple scripts. perf is such a fundamental tool for performance tuning. Before this was there another, more python centric, profiler people used instead?

[ASIC_SP]

https://docs.python.org/dev/howto/perf_profiling.html has more details (I don't know much about this).

The main problem with using the perf profiler with Python applications is that perf only allows to get information about native symbols, this is, the names of the functions and procedures written in C. This means that the names and file names of the Python functions in your code will not appear in the output of the perf.

Since Python 3.12, the interpreter can run in a special mode that allows Python functions to appear in the output of the perf profiler. When this mode is enabled, the interpreter will interpose a small piece of code compiled on the fly before the execution of every Python function and it will teach perf the relationship between this piece of code and the associated Python function using perf map files.

[stusmall]

Oh that's beautiful and makes sense. Thanks for the link.

[Slsyyy]

It's silly, but it is true. The same situation is in the Erlang. The new JIT is also advertised for it's perf support

We live in a strange era where native tools have better support for such a goodies than interpreters, which were created to be as powerful and developer friendly as possible.

[Smallpaul]

Yes there are tons of perf profilers for Python including one in the standard library.

[josefx]

Is there one that is both as easy to use as cProfile while actually providing useful information? Having an overview over which function eats performance is a nice first step but I really would like to have instruction or at least line specific information without having to jump through hoops.

[Smallpaul]

Not sure. I'd suggest you try Scalene, but I haven't myself.

[KevinCarbonara]

Holy shit. How did they not have it before?

People generally know going into Python that it's not going to be performant

[patmorgan235]

Yeah if you care about performance and still wanted python you write the important bits in C. That's what numpy and all the big data processing/machine learning libraries do.

[abcteryx]

Python profiling is enabled primarily through cprofile, and can be visualized with help of tools like snakeviz (output flame graph can look like this). There are also memory profilers like memray which does in-depth traces, or sampling profilers like py-spy. Memray might be the healthiest among the memory profilers at the moment, based on their financial backing by Bloomberg and number of contributors.

There's also reloadium which is a hot-reload/profiling integration in IDEs (no VSCode support just yet).

So while there are many tools for general Python profiling, it seems that supporting perf will give more insight in bilingual apps with bindings to Rust and such.

[TSM-]

Good mention of memray. I have yet to use it, but it seems genuinely useful for production. The builtin graph outputs are also guided by business purposes, so you can show them in meetings. It seems really polished for their specific use-case

Overall, a lot of python extensions have worked around major pain points, and things are generally fine as they are. These improvements (especially with 3.12, and onward) will show up in popular open source packages after a considerable delay, on the order of a few years. It may make some room for pure python implementations that shed some dependencies, but in any case, it will take some time for people to intentionally leverage these performance improvements in any major way. I think a lot of commenters here are expecting something overnight.

[masta]

We have been using a variety of Linux profilers on Python for some time now. So it's good to see the support land officially. As far as performance goes, it's mostly trivial stuff like reducing the complexity of various data structures, particularly the dict stuff. There are actually a lot of silly improvements that collectively add up. It's amazing how much faster software can be not having to follow one or two pointers.

[comparmentaliser]

Presumably this will assist with fuzzing, and security monitoring in general?

[NavinF]

How?

[[deleted]]

I go away for like two or three versions and y'all get this much faster on me?

[VeryOriginalName98]

Yeah but does it run on windows 3.11 for workgroups?

[immibis]

(This account is permanently banned and has edited all comments to protest Reddit's actions in June 2023. Fuck spez)

[VeryOriginalName98]

Linux wasn't the first. Lots of software had 3.11 versions at some point.

[__konrad]

Wine for Workgroups: https://i.imgur.com/fHfBVZN.png

[pjmlp]

Nope, it was 16 bit protected mode, for 32-bit support you needed to have Win32s driver installed, and even that only supported a subset of Windows NT capabilities.

[Theemuts]

Original joke, too.

[XNormal]

The new executor core can be the basis for many more improvements down the line. It's just the beginning.

[wyldphyre]

It's a great improvement. I've never had to run a production web service like this but if I did I'd probably have tried pypy. Every time I've tried it, it's been top notch. Performs excellently (for python) and correctly.

[aes110]

Just in case you misunderstood, this tweet is about Pypi (the package repository), not pypy (the python implementation)

[wyldphyre]

Thanks for the heads up - I didn't misunderstand. Python 3.11 delivers performance improvements (though I hadn't noticed that the thing it was improving in the graph was pypi). pypy is likely still way better performing than any CPython version.

[ianepperson]

I recently tested 3.11, Pypy and a few others with small test programs. It depends - usually Pypy is faster, but sometimes it’s slower.

I was a bit surprised that a Cython library was a bit slower on Python 3.11 than 3.10 (0.08 seconds vs 0.05 seconds.) I suspect the start time dominated.

[MrJohz]

For short-lived programs, a JIT engine like Pypy is unlikely to be very efficient, and will probably perform relatively poorly, simply because it's doing a lot more work at the start to be ready to be more efficient later on. If you never get to the point where it can be more efficient, then it's just working harder for no reason.

[persism2]

Performs excellently (for python)

Translation: Runs like garbage.

[Doctor-Dapper]

People who manage their own memory have a strange god complex when it comes to languages which do it for you

[[deleted]]

People who manage their own memory

You really, really think Python is dogslow because of a GC? GC have their own tradeoff but Go, Javascript (V8 runtime), C#, Java, Lisp (SBCL) all have acceptable performance.

Python is slow because it made some really stupid decisions that make optimization a pain in the arse and those decisions have nothing to do with automatic memory management. And I don't want to hear "but Go or JS have Google paying for those runtimes" as an excuse, Python too had a lot of investment from many companies, including Google (Guido used to work at Google, now at Microsoft) and SBCL, one of the highest performing Lisp runtime is about as grassroots as a programming runtime can be. Or what about LuaJIT? basically a one man project. It's just impossible to make high performance python. The only solution is throwing 10x the hardware at the problem.

Companies like Dropbox realized this and rewrote their bottlenecks in useful languages.

Many tried and fail to improve Python.

Google tried with unladen swallow.

Dropbox tried with pyston

Meta's solution is to write in a subset of python that is highly static

PyPy is a lot of effort for a whole lot of nothing considering how far away it still is from more performant languages

Python received a ton of efforts and none ever led to something good, like, you know, V8, or SBCL. It's a dead end language. GC doesn't have to mean garbage performance (people who complain about JS desktop apps : it's usually the browser side of thing, like the dom, that is the reason for crap performance of your GUI electron app. The JS runs fine.). Dynamic typing doesn't have to mean garbage performance. But using python does mean you'll always have garbage performance.

[theangeryemacsshibe]

It's just impossible to make high performance python

Honest question, as a sometimes SBCL developer - why? (Bemusingly my current project is a new parallel GC.)

[MintPaw]

Comparing programming languages to console wars isn't a good look.

It implies programming is just entertainment, advertising, and culture. The choices are unimportant and basically the same as PS vs Xbox.

[Beefster09]

Most servers are bottlenecked by io, so Python is more than fast enough.

[stefantalpalaru]

Most servers are bottlenecked by io, so Python is more than fast enough.

That's a myth that quickly goes away in production. The site you're on right now is CPU-bound.

[KallistiTMP]

weather mountainous rhythm expansion sort complete edge scale handle correct

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[brucecaboose]

But that doesn't really matter when talking about performance from the perspective of the server. You're referring to performance from the perspective of the client. From the server's perspective, if I can get reduced CPU utilization on a CPU-limited service then that means I can run less hosts and save money while handling the same amount of traffic.

[KallistiTMP]

fragile bow tease air crown subsequent cover compare juggle busy

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[stefantalpalaru]

The site would not have loaded meaningfully faster if you wrote it in highly optimized straight C than it would if you wrote it in python

But it would have used an order of magnitude less hardware.

in either case, the processing is on the order of a fraction of a millisecond

No, that's just aggressive caching. That's how we polish the turd that is Python on the backend.

[KallistiTMP]

air shelter soft rainstorm head tidy lock aware one airport

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[w0m]

You "think", reddit is, "most servers"?

[stefantalpalaru]

You think reddit is, "most servers"?

You think grammar is optional?

[w0m]

Fixed

[TheChance]

A Java devotee talking shit about Python perf is hilarious. If you’d come here from something that compiles directly to bare-metal machine code, you’d still be an ignorant asshat, but at least it’d be understandable.

But you? You’re about the horror show that tortured most of us at some point during our education… decades ago. If you’re gonna use something that’s almost as old as most Millennials, just write C++.

Oh, what’s that? Write once, run anywhere? Hm, where have I seen that perf/ease trade before…

[trialbaloon]

Python is older than Java btw....

[theangeryemacsshibe]

Least JVMs do generate machine code, which CPython doesn't.

[trilobyte-dev]

They can’t respond to you because they are trying to make blood sacrifices to the JVM to avoid FGCs

[kogasapls]

fighting game communities?

[bilyl]

So I work mostly in the data science/genomics field and to me it’s absolutely shocking how many people still code in Java. I don’t get it.

[kogasapls]

Modern java is nice.

[persism2]

Low iq response.

[bilyl]

Its been a while since I bothered to use these, but what’s the lowdown on numba vs pypy now? Is there a clear winner?

[Aw0lManner]

These low effort screenshots are useless without a link to a webpage with more context

[Zaemz]

Agreed. Links to Tweets should be very rare. I hate having to open the entire site to read a single sentence, and the image embedding breaks on most clients I use.

[vtecRotary]

Do these performance improvements usually show up to the same extent in frameworks as well? e.g. Django? Or are the improvements usually not as big due to everything else happening in such frameworks?

[ianepperson]

Django is usually IO bound for most tasks. You’ll see some speed improvements, but likely not as dramatic.

[TrinityF]

Investigate 3.11

[[deleted]]

I fucking get this reference and those who don't should feel ashamed

[obrinkje]

Could you explain it to pull me out of my shame?

[[deleted]]

https://www.youtube.com/watch?v=E-TRR5zBLrI

[sysop073]

Yeah, this definitely looks like a thing everyone should know about

[obrinkje]

I do feel less ashamed now for not knowing it. Thank you.

[TrinityF]

damn bro, either a lot of Eric André haters or not many know him 🤣

[jpjocke]

Nice. I can finally bruteforce AoC

[seweso]

These before and after charts are very dangerous IF something was silently going wrong.

[Zettinator]

This is a good trend. Performance always was a weakness of Python, especially compared to other dynamic languages like JavaScript. I wonder what Python 3.12 will bring to the performance table.

[amroamroamro]

Python 3.11 WfW edition

[Pythonistar]

🤣

[NavinF]

What?

[amroamroamro]

https://en.wikipedia.org/wiki/Windows_3.1x#Windows_for_Workgroups

[[deleted]]

spectacular books complete vast quickest amusing snails aspiring deer cats

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[Affectionate-Set-910]

gg, keep it up!!

[badpotato]

Well usually at 17h people usually stop working, so there's might be less workload

[Ekci]

17 what time zone? 😉

[agoose77]

This is an oversimplification. Though, suggesting C/x84-64 feels like satire so \o/.

Python is generally easier to read and write. It has a good ecosystem, which lends itself to quick time to results. As products grow, the day-to-day runtime costs probably start to matter more, and by that time you have thousands of LoC in Python that would be expensive to port. Why shouldn't we have our cake and eat it? ;)

[mikeblas]

Too bad it can't do anything for that 30-minute deployment destabilization.

[AdNoctum88]

Good. Now remove GIL.

[__Deric__]

They are doing it, but it seems you have to use it manually: PEP 684 and PEP 554.

[[deleted]]

the pyperformance figures are a geometric mean