Time thread synchronization

Enrico

Hi all!
I'm developing an application that use a thread for load and draw some images. When the images are drawed, I set the thread state to sleep with the WaitOne method. Then, the application wake up the thread using the Set method. Now, during the execution, the application used about one second for wake up the thread. :S

By the theory, this should be a fast operation, but it isn't. Seem the thread run synchronously, and not asynchronously, as should be.

Why it takes a lot of time?
Have you any idea about this?

Thank you a lot!

4 Replies

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Enrico16y ago
I don't want extra time! I think when I wake up a therad, I must not wait any delay cause the wake up. If there are some delays, they must be internally and not be visible to the user when use the application.
The application wake up the worker thread with the Set method. I used the AutoResetEvent class for handle the thread.
I don't understand!
Sam Hobbs16y ago
Are you saying that the second is extra time that you don't want or is it intended? I assume it is not intended. Do you know if the second is a delay in the sense that the processor is not busy doing something for a second or does the processor do some processing for a second? You need to methodicallly analyze what is happening; determine what is happening for the purpose of identifying what to analyze and what not to.

Also, how does the application wake up the worker thread?
Enrico16y ago
Thank you Sam for your response.
I have not been precise in my question. The worker thread open some images and put them into a buffer, but not draw them. The draw in the screen is made by the main thread in another time. I hope the issue is now clearer.
After the wake up by the application, the worker thread load and put the images into a buffer. When it has complete, its suspended. After, the application draw the content of buffer and wake up the worker thread that do its work.

There is a lot of time, about one second, that the application used to wake up the thread. Is it possible?
Sam Hobbs16y ago
You should not do the drawing in a worker thread. The worker thread does not own the window (form) and Windows explicitly states that windows must be accessed only by the thread that owns them; your main thread in this case. That is often violated; windows are often accessed by other threads and sometimes other processes, but the official Windows documentation states that it is not guaranteed to work. Painting (drawing) is a high-performance operation and vulnerable to problems. That might not be the problem here, but you should not do the drawing in a separate thread. The .Net library makes painting easier than when the Windows API is used directly, but that can make it more confusing for developers such as you that is not familiar with the way that Windows does graphics. It would help you if you become more familiar with the way Windows does graphics.

What does the thread do for the second after the application wakes it up?