c# - Do functions slow down performance -

i using c# go through loop , (this loop massive, big 1,000,000 records long). wanted replace inline code code exact same thing, except in function.

i guessing there slight decrease in performance, noticeable?

if have loop:

public void main() {         int x = 0;     (int = 0; < 1000; i++)     {        x += 1;     } } 

would loop slow down if did same thing except time making use of function?

public void main() {         int x = 0;     (int = 0; < 1000; i++)     {        x = incrementint(x);     } }  public int incrementint(int x) {    return x + 1; } 

edit:

• fixed logic bug, sorry that.

a method call slow down. jit compiler can inline method if set of conditions fullfilled results in assembly code equivalent first example (if fix logic bug in example).

the question indirectly asking under circumstances method inlined? there many different rules easiest way sure inlining work measure it. can use perfview find out each method why not inlined. can give jit compiler hint relax of rules , inline method .net 4.5

see http://blogs.microsoft.co.il/sasha/2012/01/20/aggressive-inlining-in-the-clr-45-jit/

there conditions described prevent inlining:

• methods marked methodimploptions.noinlining
• methods larger 32 bytes of il
• virtual methods
• methods take large value type parameter
• methods on marshalbyref classes
• methods complicated flowgraphs
• methods meeting other, more exotic criteria

if follow rules , measure can write highly performant code while keeping readable , maintainable code.