29 ms·

What poor performance? At this point, this criticism has become a "thing" that no one really expands on or enumerates as if it's a given. It's not a given, and

by zo1 6y ago

What poor performance? At this point, this criticism has become a "thing" that no one really expands on or enumerates as if it's a given. It's not a given, and at the very least is nuanced and complicated.

throwaway894345 6y ago
I’m not sure where you’re getting your information, but Python itself is quite slow (100-1000X slower than Go or Java) and it’s only “fast” when it’s dispatching to C or Rust or FORTRAN, and even then (to your point about nuance) these optimizations are only feasible sometimes; namely, when the cost of serializing is lower than the efficiencies gained by the optimizations available in the target language. This is all pretty widely discussed, including here on this very forum. No doubt that Python is sometimes fast enough (e.g., vanilla CRUD apps that do all of the heavy lifting in Postgres), but sometimes it’s not and you’re left with really crumby optimization options. And since we rarely can know with certainty on the outset of a project whether or not the bottlenecks will be amenable to the optimizations afforded by Python, it’s a dangerous game. I would even go so far as to say that other languages have become quite good at many of the things that Python is good at (namely pace of development) while being much better at the things that it’s not good at (performance, package management, etc), so I actually wouldn’t recommend starting new projects in Python except for certain niches, like scientific computing (and who knows if Python will even retain its dominance there).
- ablekh 6y ago
  I'm curious about sources for your claim of Python being 100-1000x slower than Go or Java. While the lower bound of the cited range is realistic (but only for certain problems), the majority of the range is highly unlikely. According to my sources, the difference is not that dramatic: depending on a specific type of a problem, it ranges from 1.5x to 100x. For applications using relevant Web frameworks, the composite difference is just 4-5x. As for scientific computing domain, I would start a new project in Julia rather than Python.
  - throwaway894345 6y ago
    It’s a ballpark estimate from various real world benchmarks I’ve done over the years (I’ve spent a lot of my career optimizing Python, including rewriting things on occasion). In the case of web framework benchmarks, I’m guessing that the fastest Python web frameworks are almost pure-C, and the benchmark is probably running very little actual Python code (while the Go benchmarks are pure-Go) this doesn’t extrapolate well to real world applications where the web server is never the bottleneck and your bottleneck tends to be app code that isn’t easily rewritten in C. Mostly the 100-1000X figure is intended to compare pure-Python code with pure-Go or pure-Java.
    - ablekh 6y ago
      I guess, your ballpark estimate is too rough (and/or Python 3 has improved significantly since then). The sources / benchmarks that I used to back up my claims [1-3] imply use of pure Python, not "almost pure-C". That includes Web frameworks (FastAPI that I compared to Java / Go frameworks is pure Python, which, in turn, is based on Starlette, a pure-Python implementation of an ASGI framework). [1] https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/go-python3.html https://benchmarksgame-team.pages.debian.net/benchmarksgame/... [2] https://github.com/frol/completely-unscientific-benchmarks https://github.com/frol/completely-unscientific-benchmarks [3] https://www.techempower.com/benchmarks/#section=data-r19&hw=ph&test=composite https://www.techempower.com/benchmarks/#section=data-r19&hw=...
guenthert 6y ago
Nobody would pick Python because it performs well. In many (and as performance of computers in general improves, more) cases, it performs well enough though. For one (admittedly absurd) example, where it just doesn't: a network device driver in user space: https://github.com/ixy-languages/ixy-languages https://github.com/ixy-languages/ixy-languages

by zo1 6y ago

throwaway894345 6y ago

I’m not sure where you’re getting your information, but Python itself is quite slow (100-1000X slower than Go or Java) and it’s only “fast” when it’s dispatching to C or Rust or FORTRAN, and even then (to your point about nuance) these optimizations are only feasible sometimes; namely, when the cost of serializing is lower than the efficiencies gained by the optimizations available in the target language. This is all pretty widely discussed, including here on this very forum. No doubt that Python is sometimes fast enough (e.g., vanilla CRUD apps that do all of the heavy lifting in Postgres), but sometimes it’s not and you’re left with really crumby optimization options. And since we rarely can know with certainty on the outset of a project whether or not the bottlenecks will be amenable to the optimizations afforded by Python, it’s a dangerous game. I would even go so far as to say that other languages have become quite good at many of the things that Python is good at (namely pace of development) while being much better at the things that it’s not good at (performance, package management, etc), so I actually wouldn’t recommend starting new projects in Python except for certain niches, like scientific computing (and who knows if Python will even retain its dominance there).

ablekh 6y ago
I'm curious about sources for your claim of Python being 100-1000x slower than Go or Java. While the lower bound of the cited range is realistic (but only for certain problems), the majority of the range is highly unlikely. According to my sources, the difference is not that dramatic: depending on a specific type of a problem, it ranges from 1.5x to 100x. For applications using relevant Web frameworks, the composite difference is just 4-5x. As for scientific computing domain, I would start a new project in Julia rather than Python.
- throwaway894345 6y ago
  It’s a ballpark estimate from various real world benchmarks I’ve done over the years (I’ve spent a lot of my career optimizing Python, including rewriting things on occasion). In the case of web framework benchmarks, I’m guessing that the fastest Python web frameworks are almost pure-C, and the benchmark is probably running very little actual Python code (while the Go benchmarks are pure-Go) this doesn’t extrapolate well to real world applications where the web server is never the bottleneck and your bottleneck tends to be app code that isn’t easily rewritten in C. Mostly the 100-1000X figure is intended to compare pure-Python code with pure-Go or pure-Java.
  - ablekh 6y ago
    I guess, your ballpark estimate is too rough (and/or Python 3 has improved significantly since then). The sources / benchmarks that I used to back up my claims [1-3] imply use of pure Python, not "almost pure-C". That includes Web frameworks (FastAPI that I compared to Java / Go frameworks is pure Python, which, in turn, is based on Starlette, a pure-Python implementation of an ASGI framework). [1] https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/go-python3.html https://benchmarksgame-team.pages.debian.net/benchmarksgame/... [2] https://github.com/frol/completely-unscientific-benchmarks https://github.com/frol/completely-unscientific-benchmarks [3] https://www.techempower.com/benchmarks/#section=data-r19&hw=ph&test=composite https://www.techempower.com/benchmarks/#section=data-r19&hw=...

guenthert 6y ago

Nobody would pick Python because it performs well. In many (and as performance of computers in general improves, more) cases, it performs well enough though. For one (admittedly absurd) example, where it just doesn't: a network device driver in user space: https://github.com/ixy-languages/ixy-languages https://github.com/ixy-languages/ixy-languages