Async Python is not faster

Post by Izkata » Fri, Jun 12, 2020, 6:00 PM UTC

hinkley wrote: post #225

phodge wrote: post #93

How is this result surprising? The point of coroutines isn't to make your code execute faster, it's to prevent your process sitting idle while it waits for I/O. When you're dealing with external REST APIs that take multiple seconds to respond, then the async version is substantially "faster" because your process can get some other useful work done while it's waiting. Obviously the async framework introduces some over…

I'm starting to wonder what the origin story is for titles like this. Have CS programs dropped the ball? Did the author snooze through these fundamentals? Or are they a reaction to coworkers who have demonstrated such an educational gap? Async and parallel always use more CPU cycles than sequential. There is no question. He real questions are: do you have cycles to burn, will doing so brings the wall clock time down,…

Post by fernandotakai » Fri, Jun 12, 2020, 6:06 PM UTC

GamblersFallacy wrote: post #86

calpaterson wrote: post #21

Earlier quoted context omitted.

Hi - many of the configurations do use uvloop. For what it's worth, I think people are using aiopg because it works with SQLAlchemy whereas asyncpg does not. I kept the database driver the same because I'm testing sync vs async and not database drivers. I would be interested in testing asyncpg, particularly a performance claim is a big part of that library's documentation but another time.

Hi, a few suggestions. Your benchmarks github repo requirements.txt shows uvloop is not been installed. In addition, the bash script calling uvicorn doesn't have uvloop set for the loop parameter. For example, serve-uvicorn-starlette.sh should be: uvicorn --port 8001 --workers $PWPWORKERS app_starlette:app --loop uvloop The uvicorn docs should point out what a big difference uvloop makes.

Post by rukittenme » Fri, Jun 12, 2020, 6:08 PM UTC

Jtsummers wrote: post #231

rukittenme wrote: post #108

Earlier quoted context omitted.

Whats the point of writing concurrent code if its not faster?

Contrasting with jdlshore, concurrency can make programs much easier to reason about, when done well. This is a benefit of both Go and Erlang, though they use different approaches. Concurrency can help you separate out logic that is often commingled in non-concurrent code, but doesn't need to be. As a real-world example, I used to do safety critical systems for aircraft. The linear, non-concurrent version, included a…

Post by rukittenme » Fri, Jun 12, 2020, 6:13 PM UTC

jdlshore wrote: post #213

rukittenme wrote: post #108

Earlier quoted context omitted.

Whats the point of writing concurrent code if its not faster?

Concurrency is notoriously difficult to reason about. Concurrency bugs are also a f__king nightmare to debug. Given how slow I/O operations are, and how much modern code depends on the network, we typically need some concurrency in our code. So for me, almost always, the question isn't, "which concurrency choice is fastest?" but rather, "which concurrency choice is fast enough while leading to code with the least bug…

Post by detaro » Fri, Jun 12, 2020, 6:17 PM UTC

rukittenme wrote: post #255

Jtsummers wrote: post #231

Earlier quoted context omitted.

Contrasting with jdlshore, concurrency can make programs much easier to reason about, when done well. This is a benefit of both Go and Erlang, though they use different approaches. Concurrency can help you separate out logic that is often commingled in non-concurrent code, but doesn't need to be. As a real-world example, I used to do safety critical systems for aircraft. The linear, non-concurrent version, included a…

Signals are not dependent on concurrency. And you don't need multiple processes to implement a state machine. I mean think about it. Whats the difference between sending message A and then message B versus sending messages A and B into a queue and letting some async process pop from it? Less complexity and guaranteed message delivery come for free in single-threaded code. Am I wrong? What am I missing?