Piece of code that can kill computer performance

Question

I'm searching for code in c# that can kill computer performance (CPU performance, maybe cpu - memory link performance too) as much as it is possible (it will run on 4 core box so I'm going to create 4 threads and run it simultaneously).

Should it work on int / double / numeric data type / should it have some crazy data structures (but it should not take too much memory) .

Do you have any suggestions ?

@Klaus - would also probably only occupy a single processor. — Oded, Jan 13 '11 at 14:06
Don't forget that those 4 cores could potentially have hyper-threads that you might want to run threads on too. — Roger Perkins, Jan 13 '11 at 14:13
Sometimes I have to test computers remotely and I want to check what happen which them, when they are heavily overwhelmed. — Darqer, Jan 13 '11 at 14:26
Most OS'es will prevent this from occupying `all` of the process tables. — ChristopheD, Jan 13 '11 at 18:33

score 14 · Accepted Answer · answered Jan 13 '11 at 14:04

14

Calculate PI using all processors.

answered Jan 13 '11 at 14:04

Oded

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It worked on Star Trek, it can work for you. – RQDQ Jan 13 '11 at 14:07
@RQDQ - I must have missed that episode. – Oded Jan 13 '11 at 14:07
1

Probably this one: http://www.youtube.com/watch?v=H20cKjz-bjw – Uwe Keim Jan 13 '11 at 17:19

score 6 · Answer 2 · answered Jan 13 '11 at 14:09

6

You could use parallel Linq to generate a Mandelbrot (Jon Skeet has the code readily available).

answered Jan 13 '11 at 14:09

Klaus Byskov Pedersen

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Alex J · Answer 3 · 2011-01-31T11:55:47.700

4

If you want to kill a machine's performance, try hitting the disk, because IO interrupts tend to affect everything even on a good CPU scheduler. Something like enumerating a directory of many little files, or writing a lot of big files to disk would do the trick.

edited Jan 31 '11 at 11:55

answered Jan 13 '11 at 14:37

Alex J

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Great idea enumerating like enumerating Windows directory, any more suggestion with HDD ? – Darqer Jan 13 '11 at 14:44
You can combine any other suggestion here and just write the output to a file. Make sure you flush your buffers between every write so it actually goes to disk rather than just staying in memory. – Alex J Jan 13 '11 at 14:54
There are some application that can kill system performance by disks IO you simply run it and everything stops, but I think that simple read write might have too low priority – Darqer Jan 13 '11 at 23:05
+1 Great answer, people tend to forget this aspect when considering overall system performance. – Chris O Jan 29 '11 at 20:08

score 4 · Answer 4 · answered Jan 13 '11 at 15:46

4

Have a program that writes copies of its executable to the drive multiple times for each thread. Have each of these copies of the program then triggered by the program. :)

answered Jan 13 '11 at 15:46

GWLlosa

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That's a different question altogether. :P – GWLlosa Jan 13 '11 at 15:54
2

It stops when the computer does :) – Poindexter Jan 13 '11 at 17:30
Searching for more controlled way :P – Darqer Jan 13 '11 at 23:05
You could add code that counts existing instances of the program and throttles itself at some preset limit, I suppose. – GWLlosa Jan 13 '11 at 23:09

score 3 · Answer 5 · answered Jan 13 '11 at 18:53

3

Why re-invent the wheel? Use existing Load Testing software.

answered Jan 13 '11 at 18:53

Tom Bushell

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No it must be a custom solution. – Darqer Jan 13 '11 at 23:06
3

@Darqer- "It must be custom?" Why put that kind of constraint on solving the problem? I thought you wanted to waste the computer's time, not yours. – AShelly Jan 14 '11 at 17:49
I have to be able to control it (turn it on / off) through simple tcp / ip call :). Well and second it might be interesting to implement it on my own :) kind of programming fun :) – Darqer Jan 14 '11 at 20:59

score 2 · Answer 6 · edited May 23 '17 at 11:47

2

Calculate a long sequence of prime numbers. The following link contains code that can be modified to do this..

Program to find prime numbers

edited May 23 '17 at 11:47

Community

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answered Jan 13 '11 at 14:07

Aim Kai

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score 2 · Answer 7 · answered Jan 13 '11 at 16:43

2

Call Bitmap.GetPixel, in a loop, in an image processing application.

answered Jan 13 '11 at 16:43

finnw

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score 2 · Answer 8 · answered Jan 13 '11 at 18:35

I would say: a naieve (brute force) travelling salesman implementation:

(from wikipedia):

The Travelling Salesman Problem (TSP) is an NP-hard problem in combinatorial optimization studied in operations research and theoretical computer science. Given a list of cities and their pairwise distances, the task is to find a shortest possible tour that visits each city exactly once.

score 1 · Answer 9 · answered Jan 13 '11 at 14:06

1

Brute force solving of N Queens (see wikipedia) for for example 64 queens.

Because a simple loop like this can be optimized away (sometimes only after a few minutes already running):

while(true) {
  i++;
}

answered Jan 13 '11 at 14:06

Geoffrey De Smet

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Declare `i` as volatile to prevent the optimization – finnw Jan 15 '11 at 19:22
@finnw: Even if i is a global field and i is volatile, it's still possible that the latest JVM (or a future JVM) detects that this piece of code is only run once and therefor i can be made a local variable and therefor the volatile nature becomes irrelevant. – Geoffrey De Smet Jan 16 '11 at 07:20
this is a .NET question, but I think you are wrong about Java also, because the VM cannot know that another class will not be loaded later that will read `i` by reflection. – finnw Jan 16 '11 at 12:58

score 1 · Answer 10 · answered Jan 13 '11 at 14:15

1

You can, as well, resolve a very long encrypted message, encrypted by a key such as 2048 bits. That's a killer.

answered Jan 13 '11 at 14:15

marcelo-ferraz

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score 1 · Answer 11 · answered Jan 13 '11 at 16:15

1

An open-source, multithreaded 3D modeling program rendering an extremely complex lighted scene will pound the strongest system into submission.

answered Jan 13 '11 at 16:15

Dave Swersky

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score 1 · Answer 12 · answered Feb 01 '11 at 01:28

1

Okay, how about some infinite recursion in the spirit of StackOverflow?

void deathToAllRobots(int someMeaninglessValue) {
    deathToAllRobots(someMeaninglessValue+1);
}

answered Feb 01 '11 at 01:28

JohnFx

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score 0 · Answer 13 · answered Jan 13 '11 at 14:06

0

int *x;
while(1)
{
     x = new int[10];
}

answered Jan 13 '11 at 14:06

Ahmad Farid

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8

Doesn't look much like C# – Roger Perkins Jan 13 '11 at 14:08
5

Compilers will probably optimise this one too. – moinudin Jan 13 '11 at 14:13

Piece of code that can kill computer performance

13 Answers13