charmonium.time_block 0.3.4

Time a block of code.

A decorator and a context-manager (with-statment) to time a block of code.

Quickstart

$ pip install charmonium.time_block

>>> import charmonium.time_block as ch_time_block
>>> ch_time_block._enable_doctest_logging()
>>> import time
>>>
>>> def foo():
...     with ch_time_block.ctx("bar"):
...         time.sleep(0.1)
...
>>> foo()
 > bar: running
 > bar: 0.1s

Equivalent context-manager:

>>> import charmonium.time_block as ch_time_block
>>> ch_time_block._enable_doctest_logging()
>>>
>>> def foo():
...     bar()
...
>>>
>>> @ch_time_block.decor("bar")
... def bar():
...     time.sleep(0.1)
...
>>> foo()
 > bar: running
 > bar: 0.1s

line_prof is extremely detailed and complex, which makes it more appropriate when you don’t know what to measure, whereas this package is more appropriate when you already know the bottleneck, and just want to see how slow a few functions/blocks are.

Unlike external profiling, This does not need source-code access, so it will work from .eggs.

Unlike external profiling, this package reports in realtime to logger (destination customizable). This is intended to let the user know what the code is doing right now.

> download: running
> download: 0.1s
> processing: running
> processing > decompress: running
> processing > decompress: 0.2s
> processing: 0.4s

Since this plugs into Python’s logger infrastructure, this can feed a pipeline that checks the application health (e.g. ensuring a microservice is responsive).

This records process’s increase in memory usage (relatively cross-platform method using psutil) when do_gc=True, which gives a rough estimate of the memory leaked by the block.

Like function profiling, but unlike other block-profilers, it is recurrent, and it maintains a stack.

>>> import charmonium.time_block as ch_time_block
>>> ch_time_block._enable_doctest_logging()
>>> import time
>>>
>>> @ch_time_block.decor()
... def foo():
...     time.sleep(0.1)
...     bar()
...
>>>
>>> @ch_time_block.decor()
... def bar():
...     time.sleep(0.2)
...     with ch_time_block.ctx("baz"):
...         time.sleep(0.3)
...
>>> foo()
 > foo: running
 > foo > bar: running
 > foo > bar > baz: running
 > foo > bar > baz: 0.3s
 > foo > bar: 0.5s
 > foo: 0.6s

This handles recursion.

>>> import charmonium.time_block as ch_time_block
>>> ch_time_block._enable_doctest_logging()
>>> import time
>>>
>>> @ch_time_block.decor(print_args=True)
... def foo(n):
...     if n != 0:
...         time.sleep(0.1)
...         return foo(n - 1)
...
>>> foo(2)
 > foo(2): running
 > foo(2) > foo(1): running
 > foo(2) > foo(1) > foo(0): running
 > foo(2) > foo(1) > foo(0): 0.0s
 > foo(2) > foo(1): 0.1s
 > foo(2): 0.2s

This even works for threads (or more usefully ThreadPoolExecutor).

>>> import charmonium.time_block as ch_time_block
>>> ch_time_block._enable_doctest_logging()
>>> import time
>>> from concurrent.futures import ThreadPoolExecutor
>>>
>>> @ch_time_block.decor()
... def foo():
...     time.sleep(0.1)
...     baz()
...
>>> @ch_time_block.decor()
... def bar():
...     time.sleep(0.2)
...     baz()
...
>>> @ch_time_block.decor()
... def baz():
...     return time.sleep(0.3)
...
>>> from threading import Thread
>>> threads = [Thread(target=foo), Thread(target=bar)]
>>> for thread in threads: # doctest:+SKIP
...     thread.start()
...
 > foo: running
 > bar: running
 > foo > baz: running
 > bar > baz: running
 > foo > baz: 0.3s
 > foo: 0.4s
 > bar > baz: 0.3s
 > bar: 0.5s
>>> # TODO: get a better example, with named threads

The results are programatically accessible at runtime. In the dict returned by get_stats(), the stack frame (key) is represented as a tuple of strings while the profile result (value) is a pair of time and memory used.

>>> import charmonium.time_block as ch_time_block
>>> ch_time_block._enable_doctest_logging()
>>> ch_time_block.clear()
>>> import time
>>>
>>> @ch_time_block.decor()
... def foo():
...     time.sleep(0.1)
...     bar()
...
>>>
>>> @ch_time_block.decor()
... def bar():
...     time.sleep(0.2)
...
>>> [foo() for _ in range(2)]
 > foo: running
 > foo > bar: running
 > foo > bar: 0.2s
 > foo: 0.3s
 > foo: running
 > foo > bar: running
 > foo > bar: 0.2s
 > foo: 0.3s
[None, None]
>>> ch_time_block.get_stats() # doctest:+SKIP
{('foo', 'bar'): [(0.2, 0), (0.2, 0)], ('foo',): [(0.3, 0), (0.3, 0)]}
>>> ch_time_block.print_stats() # doctest:+SKIP
foo       =  100% of total =  100% of parent = (0.3 +/- 0.0) sec =   2*(0.2 +/- 0.0) sec using (0.0 +/- 0.0) B
foo > bar =  100% of total =   66% of parent = (0.2 +/- 0.0) sec =   2*(0.1 +/- 0.0) sec using (0.0 +/- 0.0) B