GIL - Unit Foto · „CPython cannot into threads” ... Goroutines. Ruby Python Goroutines...

„CPython cannot into threads”

„CPython cannot into threads”❌

„CPython cannot into threads”„CPython can run only on single core”

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PyPyJythonCPythonIronPythonBrython

Python

C

„CPython cannot into threads”„CPython can run only on single core”

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„CPython cannot into threads”„CPython can run only on single core”"CPython process can execute Python bytecode in one thread at the time"

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❌

✓

kolodziejj.info@unit03

Disclaimer

So what’s the hassle?

Misconceptions

CC-SA-BY, http://dibujando.net/dib/cthulhu-96836

Evolution

Concurrencyvs.

parallelism

GILfinally

Protectorof

CPython realm

Reference counters

1. Tracing garbage collection2. Reference counting3. ...

1. Tracing garbage collection2. Reference counting

int


3


0

Internal global state

C-mutable data structuresdict, list, …

C-mutable data structuresdict, list, …str, tuple, int

Binary modulesand extensions

In single-threaded code?It doesn’t matter

(duh)

On single core?It doesn’t matter

In multi-threaded I/O-bound code?

It may not matter

With binary extensions?It may not matter

>= 3.2

1

2

Can Ihas GIL?

Nope.

1

2switch interval

2

1

Can Ihas GIL?

2

1

Can Ihas GIL?

Yes!

2

1

Can Ihas GIL?

Nope.

2

1

gil_drop_request = 1

2

1

gil_drop_request?

2

1

switch_cond?gil_last_holder?

<= 2.7- 2010

„ticks”

>>> print(„foo”)>>> -1 in range(100000000)

>>> print(„foo”)>>> -1 in range(100000000)>>> n -= 1

„check”„check” „check”

N „ticks” N „ticks” N = 100

100s ms few ms

2

1

Can Ihas GIL?

Nope.

And now? And now?

Nope. Nope.

2

1

Can Ihas GIL?

Nope.

And now? And now?

Nope. Nope.

Aw yiss


(but: STM)

RubyPythonGo

RubyPythonGoroutines

RubyPythonGoroutineschannels

multiprocessingimport

multiprocessingbinary extensions

cdef int foo = 0


cdef int foo = 0with nogil: ...


Py_BEGIN_ALLOW_THREADS Py_END_ALLOW_THREADS

multiprocessingbinary extensionsasynchronous I/O

Revolution?

Requirements

1. Single-threaded and multi-threaded I/O-bound performance2. C extensions compatibility3. Complexity

Free-threading patch

Free-threading patchsubinterpreters


GILectomy


GILectomybuffered

reference counting


GILectomy

thread

-privat

e

locking

buffered

reference counting


GILectomy

thread

-privat

e

locking

buffered

reference counting

immortal objects

--without-gilPy_LOCK(o)Py_UNLOCK(o)


GILectomy

What to do?

What to do?nothing

What to do?nothing

more research

What to do?nothing

more researchmigrate to 3.5 (3.6 even!)

What to do?nothing


assert the baseline, then act

kolodziejj.info/talks/gil/

Thank you! :)

kolodziejj.info/talks/gil/

What to do?nothing


assert the baseline, then actcontribute !

GIL - Unit Foto · „CPython cannot into threads” ... Goroutines. Ruby Python Goroutines...

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