Performance tools

and

Testing techniques

Context

  • What is performance?
  • Benchmark testing
  • Snake tools
  • Memory
  • Testing
  • T and/or B DD
  • Testing techniques
  • Testing Ontology

What is Performance?

The speed at which a computer operates, either theoretically during a benchmart test. The benchmark test usually involves some combination of work that attempts to imitate the kinds of work the computer does during actual use. Sometimes performance is expressed for each of several different benchmarks.

The total effectiveness of a computer system, including throughput, individual response time , and availability.

Benchmark Testing

Involves both developers and database administrators (DBAs) to determine current performance and make changes to improve the performances of the same.

  • Benchmark Testing should be performed on the same environment with the exact same parameters under same conditions so that we can compare the results.

  • Other applications should not be in active state other than the ones that are required for testing purposes.

  • The SW and HW components should be in-line with the specifications of the production environment.

What is code profiling?

  • A profile is a set of statistics that describes how often and for how long various parts of the program executed.
  • Python provides 3 different implementations of the same profiling interface: cProfile, profile and hotshot
  • Use together with timeit to perform benchmark testing

cProfile

  • ncalls - the number of calls

  • tottime - the total time spent in the given function ( excluding time made in calls to sub-functions)

  • percall - is the quotient of tottime divided by ncalls

  • cumtime - is the cumulative time spent in this and all subfunctions (from invocation till exit).

  • percall - is the quotient of cumtime divided by primitive calls

  • filename:lineno - provides the respective data of each function

Returned data

cProfile Usages


python -m cProfile [-o output_file] [-s sort_order] myscript.py
from cProfile import Profile

profiler = Profile()
profiler.runcall(self._handle, *args, **options)
# profiler.run(self._handle, 'output')
profiler.print_stats()

Memory Profiler

from memory_profiler import profile

@profile(precision=4)
def my_func():
    a = [1] * (10 ** 6)
    b = [2] * (2 * 10 ** 7)
    del b
    def _inner(a):
        a *= 5
    _inner(a)
    return a

if __name__ == '__main__':
    my_func()

Memory Profiler

Line #    Mem usage    Increment   Line Contents
================================================
     3  30.9102 MiB   0.0000 MiB   @profile(precision=4)
     4                             def my_func():
     5  38.5508 MiB   7.6406 MiB       a = [1] * (10 ** 6)
     6 191.1445 MiB 152.5938 MiB       b = [2] * (2 * 10 ** 7)
     7  38.5547 MiB -152.5898 MiB       del b
     8  38.5547 MiB   0.0000 MiB       def _inner(a):
     9  69.6445 MiB  31.0898 MiB           a *= 5
    10  69.6445 MiB   0.0000 MiB       _inner(a)
    11  69.6445 MiB   0.0000 MiB       return a
python -m memory_profiler profile_example.py

Memory Profiler

from memory_profiler import profile

@profile
def my_func():
    a = 'Roza'
    a = a * 55
    b = [2] * (2 * 10 ** 7)
    del b
    return a

if __name__ == '__main__':
    my_func()
python profile_example.py 

Line #    Mem usage    Increment   Line Contents
================================================
     3     30.8 MiB      0.0 MiB   @profile
     4                             def my_func():
     5     30.8 MiB      0.0 MiB       a = 'Roza'
     6     30.9 MiB      0.0 MiB       a = a * 55
     7    183.4 MiB    152.6 MiB       b = [2] * (2 * 10 ** 7)
     8     30.9 MiB   -152.6 MiB       del b
     9     30.9 MiB      0.0 MiB       return a

Memory Usage Profiler

import time
from memory_profiler import memory_usage

def f(a, n=101):
    time.sleep(2)
    b = [a] * n
    time.sleep(1)
    return b

print(memory_usage((f, (1,), {'n' : int(1e6)}))) # f - what we call, 1 - interval, n - the whole time

Snake Tools

SnakeViz

RunSnakeRun

Profiling and SnakeViz demo

Benchy

Testing

  • SOLID
  • TDD
  • BDD
  • AAA
  • Techniques

SOLID PRINCIPLES

  • S - Single-responsiblity principle
  • O - Open-closed principle
  • L - Liskov substitution principle
  • I - Interface segregation principle
  • D - Dependency Inversion Principle

AAA

  • Arrange
  • Act
  • Assert
  • Given
  • When
  • Tehn

Test Techniques

  • Fake it, till you make it
  • From the inside to the outside
  • Single Assert statement
  • Assert First
  • Triangulation
  • One 2 Many
  • Tests are specifications

"First make it work,

then make it right,

then make it fast & small."

                             Kent Beck

 

Thank you for the attention!

Performance Tools

By Rositsa Zlateva

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Performance Tools

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