Is there a speed benefit to using unsafe code in .Net to swap objects of complex types?

Question

Here is my current swap code for swapping 2 KeyValuePair objects in an array:

KeyValuePair<int, T> t = a[i]; a[i] = a[j]; a[j] = t;

Would there be any speed advantage to using unsafe code and merely swapping the pointers of the 2 objects? Or does the complier effectively boil this safe code down to effectively doing just that?

Just FYI: KeyValuePair<TKey, TValue> is a value type, so those aren't "pointers" in the array; they're the values themselves (each consisting of a TKey and a TValue) -- though, obviously, TKey and/or TValue could be reference types. — Dan Tao
– Dan Tao, Commented Oct 17, 2010 at 19:21
Ah, right, KeyValuePair is a struct, not a class. Thanks @Dan. — IamIC
– IamIC, Commented Oct 17, 2010 at 19:32

SLaks · Accepted Answer · 2010-10-17 19:34:35Z

4

No, it won't be any faster.

This is premature micro-optimization at its worst.

In fact, it will be orders of magnitude slower, since you'll need to pin the array (using the fixed keyword) in order to get a pointer to it.

edited Oct 17, 2010 at 19:34

answered Oct 17, 2010 at 19:15

SLaks

891k182 gold badges1.9k silver badges2k bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Blindy Over a year ago

Not to mention that with marshalling data across managed/unmanaged boundaries, it will most likely be WORSE.

SLaks Over a year ago

@Blindy: Wrong; that's only for COM and P/Invoke.

IamIC Over a year ago

Just asking purely from an "understanding the framework" point of view.

Pritesh · Accepted Answer · 2012-04-19 17:38:27Z

There is a space for .Net pointers in per optimization. Not much in your particular case but stuff like Circular Redundancy Check, pointers can give us more optimum solution.

Collectives™ on Stack Overflow

Is there a speed benefit to using unsafe code in .Net to swap objects of complex types?

2 Answers 2

3 Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Related