String concatenation benchmark

bench.txt

▶ for ver in "3.7.1" "3.7.2" "3.7.3" "3.7.4" "3.7.5" "3.8"
do
   echo "\nPython $ver"
   docker run --rm -v `pwd`:/app python:$ver python /app/bench.py
done

Python 3.7.1
    # components     |    join_time (μs)    |   buffer_time (μs)   |   concat_time (μs)  
-----------------------------------------------------------------------------------------
10                   |    2.80 (± 0.10)     |     3.3 (± 0.1)      |    2.45 (± 0.07)    
100                  |       22 (± 1)       |     22.9 (± 0.8)     |     20.2 (± 0.5)    
1000                 |      209 (± 6)       |      221 (± 5)       |      220 (± 10)     
10000                |     2160 (± 60)      |     2220 (± 80)      |     2260 (± 80)     

Python 3.7.2
    # components     |    join_time (μs)    |   buffer_time (μs)   |   concat_time (μs)  
-----------------------------------------------------------------------------------------
10                   |    2.80 (± 0.07)     |    3.33 (± 0.06)     |    2.44 (± 0.04)    
100                  |     21.0 (± 0.6)     |     23.1 (± 1.0)     |     20.7 (± 0.6)    
1000                 |      207 (± 5)       |      217 (± 6)       |      222 (± 5)      
10000                |     2090 (± 50)      |     2300 (± 100)     |     2440 (± 100)    

Python 3.7.3
    # components     |    join_time (μs)    |   buffer_time (μs)   |   concat_time (μs)  
-----------------------------------------------------------------------------------------
10                   |     2.8 (± 0.2)      |    3.34 (± 0.08)     |    2.40 (± 0.07)    
100                  |     21.5 (± 0.8)     |     23.2 (± 0.7)     |     20.4 (± 0.4)    
1000                 |      209 (± 4)       |      250 (± 50)      |      219 (± 6)      
10000                |     2130 (± 60)      |     2240 (± 90)      |     2240 (± 40)     

Python 3.7.4
    # components     |    join_time (μs)    |   buffer_time (μs)   |   concat_time (μs)  
-----------------------------------------------------------------------------------------
10                   |    2.32 (± 0.05)     |     3.0 (± 0.2)      |     2.1 (± 0.1)     
100                  |     17.9 (± 0.4)     |       21 (± 2)       |     16.8 (± 0.8)    
1000                 |      176 (± 4)       |      190 (± 4)       |      173 (± 4)      
10000                |     1900 (± 200)     |     2000 (± 100)     |     1800 (± 90)     

Python 3.7.5
    # components     |    join_time (μs)    |   buffer_time (μs)   |   concat_time (μs)  
-----------------------------------------------------------------------------------------
10                   |    2.34 (± 0.05)     |     2.9 (± 0.1)      |    2.01 (± 0.07)    
100                  |     18.1 (± 0.5)     |     19.6 (± 0.7)     |       17 (± 1)      
1000                 |      174 (± 5)       |      183 (± 4)       |      175 (± 5)      
10000                |     1800 (± 70)      |     1900 (± 100)     |     1740 (± 40)     

Python 3.8
    # components     |    join_time (μs)    |   buffer_time (μs)   |   concat_time (μs)  
-----------------------------------------------------------------------------------------
10                   |    2.56 (± 0.03)     |     3.2 (± 0.1)      |     3.0 (± 0.8)     
100                  |     18.4 (± 0.4)     |     19.9 (± 0.8)     |     19.5 (± 0.3)    
1000                 |      186 (± 7)       |      192 (± 7)       |      210 (± 10)     
10000                |     1870 (± 50)      |     2000 (± 100)     |     2080 (± 40)