Question

I need to check memory continuously for a change to notify, and I use System.Threading.Timer to achieve it. I want the notification ASAP, so I need to tun callback method quite often, and I don’t want cpu to use 100% to do this.

Can anybody tell me how should I set the interval of this timer? (I think it would be good to set it minimum as possible as)

Thanks

Answer 1

OK, so there is a very basic strategy for how you can be immediately notified of a modification to the dictionary without incurring any necessary CPU cycles and it involves using Monitor.Wait and Monitor.Pulse/Monitor.PulseAll.

On a very basic level, you have something like this:

public Dictionary<long, CometMessage> Messages = new Dictionary<long, CometMessage>();

public void ModifyDictionary(int key, CometMessage value)
{
    Messages[key] = value;
    Monitor.PulseAll(Messages);
}

public void CheckChanges()
{
    while(true)
    {
        Monitor.Wait(Messages);
        // The dictionary has changed!
        // TODO: Do some work!
    }
}

Now, this is very rudimentary and you could get all sorts of synchronization issues (read/write), so you should look into Marc Gravell’s implementation of a blocking queue and apply the same logic to your dictionary (essentially making a blocking dictionary).

Furthermore, the above example will only let you know when the dictionary is modified, but it will not inform you of WHICH element was modified. It’s probably better if you take the basics from above and design your system so you know which element was last modified by perhaps storing the key (e.g. last key) and just checking the value associated with it.