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I am writing a DLL in C# and I need, (not want), to limit the usage of the DLL within a specific time.
I want it to stop working after N hours from the start of the usage, while notifying the user.
And if the DLL is not used for M hours, also stop the usage (as a sort of keep alive).
Usage being calling one of the functions of the DLL.
Using exceptions always collide with the availability of the DLL (I can't keep it in blocking).
I would very appreciate any help I can get, I am not very experienced using C#.
Any solution in any language will be great, obviously I am running on a windows computer but its components (service pack etc.) can be easily modified, if any modification is needed.
Your help is very much appreciated, thank you.
EDIT
I think I wasn't clear.
What I need is notifying the user of the end of the usage of the functions in the DLL, so he could initialize those functions again if he wants.
The DLL is not unloaded.
And I don't want to interfere with the main program process, the one using the DLL functions.
use a timer:
System.Threading.Timer t = new System.Threading.Timer(End, null, N * 60 * 1000, Timeout.Infinite);
private static void End(object state)
{
// Tell the user and end the program
}
for not used use another timer:
System.Threading.Timer t2 = new System.Threading.Timer(End, null, M * 60 * 1000, Timeout.Infinite);
now i don't know what "used" mean for you, but in any function that is considered a "use" do:
t2.Change(M * 60 * 1000, Timeout.Infinite);
to end the program you can use:
Environment.Exit(0);
keep in mind, that if you have more then one thread you'll might get a zombie, so make sure that all other threads other then the main thread are Background or that you abort them or single them to close.
Now i understand that you only want to notify the user...
so what i suggest is using:
MessageBox.Show(this, "what message you want to give the user");
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From what I know it is rather known that c# can not be accurate when timing is critical. I certainly can understand that but was hoping there were known game hacks to help my issue.
tech:
I'm using an API for USB that sends data over a control transfer. In the API I get an event when an interrupt transfer occurs (one every 8 ms). I then simply fire off my control transfer at that exact time. What I have noticed, however not often, is that it takes more then 8ms to fire. Most of the time it does so in a timely matter (< 1ms after the interrupt event). The issue is that control transfers can not happen at the same time of an interrupt transfer so the control transfer must be done with in 5ms of the interrupt transfer so that it is complete and the interrupt transfer can take place.
So usb stuff aside my issue is getting an event to fire < 5ms after another event. I'm hoping there is a solution for this as gaming would also suffer form this sort of thing. For example some games can be put in a high priority mode. I wonder if that can be done in code? I may also try a profiler to back up my suspicions, it may be something I can turn off.
For those that want to journey down the technical road, the api is https://github.com/signal11/hidapi
If maybe someone has a trick or idea that may work, here are some of the considerations in my case.
1) usb interrupt polls happen ever 8 ms and are only a few hundred us long
2) control transfer should happen once every 8-32 ms (fast the better)
3) this control transfer can take up to 5 ms to complete
4) Skipping oscillations is ok for the controller transfer
5) this is usb 1.1
This is not even a C# problem, you are in a multi tasking non-realtime OS, so you don't know when your program is going to be active, the OS can give priority to other tasks.
Said that, you can raise the priority of the program thread, but I doubt it will solve anything:
System.Threading.Thread.CurrentThread.Priority = ThreadPriority.Highest;
When such restrictive timmings must be met then you must work at kernel level, per example as a driver.
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I want to be able to use more threads in a for loop.
Why is because each loop is runnings proccess which it needs to wait to exit for.
And currently it doesn't seem to be even close to 100% my CPU, and looking at the performance most of the stuff is from waiting for the processes.
My code is pretty much like this now:
Parallel.For(0, count, i =>
{
........
});
Everything is synced afterwards so it doesn't matter how many threads run per say.
They don't need to sync data during their run or anything so there it's free run in that regard.
Thanks.
EDIT:
Okay i tried looking for what actually makes it slow.
And for some reason it does take the CPU,
it just doesn't show it, probably cause it's being run "Console Window Host"?
In that case the limit is indeed the CPU, damn it -_-.
Still, why doesn't it show up as a normal process?
It's basically:
using (Process pRocess = new Process())
{
pRocess .StartInfo.Filename = "somefile.exe";
work work and also, maybe more work.
pRocess.WaitForExit();
}
Maybe you mean
Parallel
.For(0, 10, new ParallelOptions() {MaxDegreeOfParallelism = 10},
i =>{ Console.WriteLine(Thread.CurrentThread.ManagedThreadId); });
but notice, that this is not number of threads. More info here https://msdn.microsoft.com/en-us/library/system.threading.tasks.paralleloptions.maxdegreeofparallelism%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396
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I have a timer in my application that fires every 10 ms. I know this is a very small value for a Windows timer and aware of the precision issues. Anyway, it causes the CPU usage to increase to 10% on average and the memory usage is slowly increasing but then eventually goes back down to a lower value. Without the timer, there are no CPU or memory issues. From what I've read, the memory increasing and then decreasing is a normal thing and it is due to Windows not releasing memory unless it has to. However, is this going to cause any performance problems with my application? Is 10% CPU usage going to cause problems as well? When I increase the timer to 100 ms it seems to be a little better but still seeing a similar type of effect. I need the timer interval to be as small as possible.
A 10% CPU usage (in my opinion) is not a big deal. I mean it's ok but definitly not the best. It's ok if you will need to do a lot of extra stuff to achieve better performance.
I wrote a lot of apps that uses 20% CPU and it works kinda fine. However, a timer set to 10ms is kind of weird. I guess you want to use it to constantly check for something. If you are doing that, don't use timers at 10ms. It's better to use events to do this. If you don't know events, here is a simple guide.
You declare an event like this:
public event EventHandler SomethingHappened;
For the purpose of this example, I will put the event in a class called MyClass. When you want to raise the event i.e. make the event occur, do this:
SomethingHappened (this, EventArgs.Empty);
Now let's see how do you subscribe to the event. Of course you need to create an object:
MyClass obj = new MyClass ();
And then write a method to execute when the event happened. The return value type and parameters must be the same as this one:
public void DoSomething (object sender, EventArgs e) {
}
Now you do the subscription:
obj.SomethingHappened += DoSomething;
For more information, here's an MSDN tutorial:
https://msdn.microsoft.com/en-us/library/aa645739(v=vs.71).aspx
SOLVED. The issue was that I had some code in the timer event that was slowing everything down. After replacing a few lines of code the CPU usage went back down to 0% and memory is no longer increasing. Hopefully this may help someone else in the future.
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I am facing a strange issue that throws following exception.
The CLR has been unable to transition from COM context 0x22f3090 to COM context 0x22f32e0 for 60 seconds. The thread that owns the destination context/apartment is most likely either doing a non pumping wait or processing a very long running operation without pumping Windows messages. This situation generally has a negative performance impact and may even lead to the application becoming non responsive or memory usage accumulating continually over time. To avoid this problem, all single threaded apartment (STA) threads should use pumping wait primitives (such as CoWaitForMultipleHandles) and routinely pump messages during long running operations.
So, I am keen to know its possible reasons in wpf. As of now, I am performing an operation which is causing this So, I put stop watch and check the time of my code but my code is not taking time to execute rather it is taken by run time framework. I know probably I am doing something wrong with my code. So, I am keen to know the possible reason for this kind of bug.. currently Invoking that operation is taking more than 5 minutes and even operation is very simple
After doing lots of efforts, I came to know that I was making a silly mistake by putting a data grid inside a scroll bar, which disables the by default visualization(UI and Data), and It was trying to load all the objects in the grid regardless of their need,
So, good note:
Never ever place scroll bar outside a **grid.
<ScrollViewer>
<DataGrid>
....
</DataGrid>
</ScrollViewer>**
Never do this.
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I have a asp.net web page in which the button click event process runs for 35 minutes and in the front end I am using ajax and showing a progress bar image. If the process (button click event) completes in less than 30 minutes then page reloads successfully, else "in progress" image keeps showing even after the process is completed, until the time of AsyncPostBackTimeout (which is set to 60 minutes) and shows server time out issue after 60 minutes.
Please let me know if there is something I am doing wrong.
Without seeing your code, I can't tell you what's going wrong. However, I can recommend a couple of options:
Break the task out in to multiple steps (instead of one long chained task). it may be a little more work for the user, but at least they're not left hanging on a page for a half hour+ (ouch!).
Use a profiler to see what's actually taking so long and see if you can't optimize the code to cut down on the process. For example, if it's a database call it may make sense to make a stored procedure instead of multiple select/updates (with data doing back and forth)--keep the processing on the machine until the final result is needed.
For long tasks, it may make sense to break the process out in to a service or separate entity (and just have the service report back progress). For example MSMQ is a great way to have a dedicated service running and pass tasks off to it when needed. Just keep in mind, this now creates another layer which is one more place to maintain.
If a process takes 30 minutes, it could tomorrow take 60 minutes or more just because your servers will be busy doing other things. The approach is then fundamentally wrong.
My advice would be to put such long tasks to another layer, a system service. The service runs, picks tasks from a queue, executes one by one. The front layer just peeks every few seconds/minutes to see if the operation is complete. Or even better, users do not wait, they do other things and eventually somehow they are informed that the long-running task is complete.