Hi Jeremy,

On Jan 16, 2009, at 04:52, Jeremy Pereira wrote:

On 15 Jan 2009, at 22:16, Jens Bauer wrote:

..often used around 3ms for the empty method "-renderObject".
It gave me the terrible result of up to 21ms spent in the empty method!

-So I'd like to let you know that it's sometimes good to think "do I really need this method?" I will be rewriting around 8 of my large files for doing some rendering, so they will be using C-routines instead of ObjC methods, since I'm using them in a real-time environment.

My guess is that the message dispatcher probably needs to do something else than servicing *my* application, so I believe it's the nature of the environment, not a bug

I compiled your program into an Xcode project. I got an answer of 0.021ms.

I modified the project to call renderObject 1,000 times and I got the answer 0.028ms.

The only thing I can think of is that you have confused milliseconds and microseconds.

I believe that it depends on if the application is doing something else, rather than just an empty loop. In my case, I have at least one extra thread running, sometimes more threads. The project is running on a G5 DP/2.0GHz, and will not be used on intel machines, so many of you might get faster execution times than me. -But the 'warning' isn't about the average value, it's about the peak value, which sometimes takes ages, and when doing a real-time app, it might be important to avoid such peak values.

I changed the NSLog to report microseconds instead of milliseconds, and to avoid sending a million of lines, I recorded the max peak values:

        if(renderTime > maxRender)
        {
                maxRender = renderTime;
                NSLog(@"time: %.03fus", renderTime);
        }

1/16/09 08:36:53 MyApplication[22784] time: 2552.000us
1/16/09 08:37:33 MyApplication[22784] time: 3467.000us
1/16/09 08:38:34 MyApplication[22784] time: 3705.000us
1/16/09 08:40:36 MyApplication[22784] time: 3872.000us
1/16/09 08:46:41 MyApplication[22784] time: 6753.000us
1/16/09 08:53:20 MyApplication[22784] time: 7985.000us

When I use only C-routines, I get no high peak values.


Love,
Jens

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