在Jupyter Notebook中使用cython进行行轮廓分析 [英] Line profiling with cython in jupyter notebook

问题描述

我正在尝试在具有cython功能的jupyter笔记本中使用Liner_profiler库.它只在中途工作.我得到的结果仅包含该函数的第一行，而没有分析结果.

I'm trying to use liner_profiler library in jupyter notebook with cython function. It is working only halfway. The result I get only consist of first row of the function and no profiling results.

%%cython -a
# cython: linetrace=True
# cython: binding=True
# distutils: define_macros=CYTHON_TRACE_NOGIL=1
import numpy as np
cimport numpy as np
from datetime import datetime
import math


cpdef np.int64_t get_days(np.int64_t year, np.int64_t month):
    cdef np.ndarray months=np.array([31,28,31,30,31,30,31,31,30,31,30,31])
    if month==2:
        if (year%4==0 and year%100!=0) or (year%400==0):
            return 29
    return months[month-1]

对于分析结果，int只能显示一行代码

For the profiling result int onlt shows one line of code

    Timer unit: 1e-07 s

Total time: 0.0015096 s
File: .ipython\cython\_cython_magic_0154a9feed9bbd6e4f23e57d73acf50f.pyx
Function: get_days at line 15

Line #      Hits         Time  Per Hit   % Time  Line Contents
==============================================================
    15                                           cpdef np.int64_t get_days(np.int64_t year, np.int64_t month):

推荐答案

这可以看作是line_profiler中的错误(如果应该支持Cython).要获取配置文件功能的代码，line_profiler 读取pyx-文件，并尝试在inspect.getblock的帮助下提取代码:

This can be seen as a bug in the line_profiler (if it is supposed to support Cython). To get the code of the profiled function, line_profiler reads the pyx-file and tries to extract the code with help of inspect.getblock:

...
# read pyx-file
all_lines = linecache.getlines(filename)
# try to extract body of the function strarting at start_lineno:
sublines = inspect.getblock(all_lines[start_lineno-1:])
...

但是，getblock对cpdef函数一无所知，因为python仅具有def函数，因此产生错误的函数体(即仅签名).

However, getblock knows nothing about cpdef-function, as python has only def-functions and thus yields wrong function-body (i.e. only the signature).

解决方法:

一个简单的解决方法是引入一个虚拟def函数，该函数将成为cpdef函数的哨兵，从而使inspect.getblock产生cpdef函数的整个主体+前哨功能的主体，即:

A simple work around would be to introduce a dummy def-function, which would be a sentinel for the cpdef-function in such a way, that inspect.getblock would yield the whole body of the cpdef-function + body of the the sentinel function, i.e.:

%%cython
...
cpdef np.int64_t get_days(np.int64_t year, np.int64_t month):
    ...

def get_days_sentinel():
    pass

，现在报告%lprun -f get_days get_days(2019,3)如下所示:

Timer unit: 1e-06 s

Total time: 1.7e-05 s
File: XXXX.pyx
Function: get_days at line 10

Line #      Hits         Time  Per Hit   % Time  Line Contents
==============================================================
    10                                           cpdef np.int64_t get_days(np.int64_t year, np.int64_t month):
    11         1         14.0     14.0     82.4      cdef np.ndarray months=np.array([31,28,31,30,31,30,31,31,30,31,30,31])
    12         1          1.0      1.0      5.9      if month==2:
    13                                                   if (year%4==0 and year%100!=0) or (year%400==0):
    14                                                       return 29
    15         1          2.0      2.0     11.8      return months[month-1]
    16                                           
    17                                           def get_days_sentinel():
    18                                               pass

前哨上还有一些难看的尾随线，但最好是根本不看任何东西.

There are still somewhat ugly trailing lines from the sentinel, but it is probably better as not seeing anything at all.

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