Is using Sleep an ideal solution here?

[cartographer]

Hi all,

I have made a multithreaded server that sends client the updates
of its desktop. Server uses a seprate thread that gets updates
and then send them to client through socket. I have used
an infinite while loop in that thread that breaks when client disonnects
and in each iteration of loop i get updates and sends if there is any.
After sending one update i have used a Sleep of 50ms so that there
should be a delay in next update send. If i dont used the sleep then
server thread will continuously get screen updates and sends them.
This causes my CPU usage on server near to 100%. To avoid this i have used
sleep. Is that sleep duration is ideal or poor approach?
Or i can use more sleep duration.

I havent any idea how much sleep is ideal in real time applications.

[harshandu]

HI ,

What i feel is, if u use sleep and if there are any updates at that time then you will miss those updates.so,instead of sending the updates in that thread,put the updates in a message queue and create another thread which continously watches the message queue,so if there are any messages(updates) then it sends the data to the particular client.

Regards,
Harsh.

[Andreas Masur]

If I understood correctly you are basically having an event-based approach. The server gets an event (-> send update), on this event it needs to send the data to the client.

In this case, I would rather use an event to indicate the send thread that data should be sent. This way, you are not relying on any time that might not be accurate in regard to the updates.

If however, the send thread is responsible for getting the update itself before sending it, then a 'Sleep()' is sufficient here...

[cartographer]

Thanx

Actually i m using a System wide hooking dll(developed in VC++6.0) that sends my server (developed in C#) the coordinates of the the rectangle
that windows is going to paint before the paint actually happens in the form
of a message. My server gets the msg from its message queue(server main thread). Then server takes union of the rectangles arrived to make a single rectangle. The other thread that is responsible for capturing and sending the updated region checks the that single rectangle frequently to ensure whether to capture and send an update or not. If the rectangle is empty then this thread doesnt capture anything and sleeps for 50ms. After 50ms that thread again checks the rectangle set by the main thread. That process continues. It all works fine but one of my friends says that i should not use sleep if i dont use it then server CPU usage can go to 100% if there are contninuous updates, thats not feasible.

[leojose]

It all works fine but one of my friends says that i should not use sleep if i dont use it then server CPU usage can go to 100% if there are contninuous updates, thats not feasible.

When you say 'fine' do you mean that it meets your expectations?
You may have to use trial-error to find an appropriate Sleep() duration that will give you acceptable CPU usage and Update rate.