What are some common performance issues regardless of programming language?

Question

Normally, if my code has performance issues, I will follow the steps below to understand the reason.

• top command to view processor usage
• free command to view memory usage
• add time information to code
• print execution instructions in code
• understand and improve the algorithm

What do you do if your code is very slow.

Answer 1

1) ,
2) , , 2 .

Answer 2

. .

Answer 3

, , , - .

, , , , , .

, ,

• accepts samples of the time stack on the clock (during I / O, as well as processor time),
• when you want them (when it's slow, not all the time),
• and reports on a line of code (and not just on function / method)
• percentage of samples containing this line (not count, not time, not average time — percent).

Good Zoom .

Another very simple method is a random pause .