Is there some reason that identical math operations would take significantly longer in one Silverlight app than in another?
For example, I have some code that takes a list of points and transforms them (scales and translates them) and populates another list of points. It's important that I keep the original points intact, hence the second list.
Here's the relevant code (scale is a double and origin is a point):
public Point transformPoint(Point point) {
// scale, then translate the x
point.X = (point.X - origin.X) * scale;
// scale, then translate the y
point.Y = (point.Y - origin.Y) * scale;
// return the point
return point;
}
Here's how I'm doing the loop and timing, in case it's important:
DateTime startTime = DateTime.Now;
foreach (Point point in rawPoints) transformedPoints.Add(transformPoint(point));
Debug.Print("ASPX milliseconds: {0}", (DateTime.Now - startTime).Milliseconds);
On a run of 14356 points (don't ask, it's modeled off a real world number in the desktop app), the breakdown is as follows:
Silverlight app #1: 46 ms
Silverlight app #2: 859 ms
The first app is an otherwise empty app that is doing the loop in the MainPage constructor. The second is doing the loop in a method in another class, and the method is called during an event handler in the GUI thread, I think. But should any of that matter, considering that identical operations are happening within the loop itself?
There maybe something huge I'm missing in how threading works or something, but this discrepancy doesn't make sense to me at all.
In addition to the other comments and answers I'm going to read between the lines a little.
In the first app you have pretty much this code in isolation running in the MainPage constructor. IWO you've create a fresh Silverlight app and slapped this code in it and thats it.
In the second app you have more actual real world stuff. At the very least you have this code running as the result of a button click on a rudimentory UI. Therein lies the clue.
Take a blank app and drop a button on it. Run it and click the button, what does the button do? There are animations attached to visual states of the button. This animation (or other animations or loops) are likely running in parrallel with your code when you click the button. Timers (whether you do it properly with StopWatch or not) record elapsed time, not just the time your thread takes. Hence when other threads are doing other things (like animations) your timing will be off.
My first suspicion would be that Silverlight App #2 triggers a garbage collection. Scaling ~15,000 points should be taking a millisecond, not nearly a second.
Try to reduce memory allocations in your code. Can transformedPoints be an array, rather than a dynamically grown data structure?
You can also look at the GC performance counters, but simply reducing the memory allocation may turn out to be simpler.
Could it be possible your code is not being inlined in the CLR by the app that is running slower?
I'm not sure how the CLR in SL handles inlining, but here is a link to some of the prerequisites for inlining in 3.5 SP1.
http://udooz.net/blog/2009/04/clr-improvements-in-net-35-sp1/
Related
I was initially going to write what looked like a four paragraph essay to explain what I'm working on, but it wasn't nessecary. In summary, I'm a rookie at Unity and know very little about how to create a platform in which I can store(send and retrieve from other clients) data in "the cloud". Yet, I need to be able to do so for my project.
using System.Collections.Generic;
using UnityEngine;
public class MultiplayerMoveMe : MonoBehaviour
{
//Note: I am making a retro-style game where all sprites face the camera, so the rotation of the players is not a factor that needs considering here; just the position.
//I have a fleshed-out idea on how I will do all of this, however I am completely foreign in all things server-related on this scale so I need some assistance(not the most prideful circumstances).
public GameObject p2Obj;
void Start()
{
//Anything that I might need to add that the serverGet() function might require
}
void serverGet(int playerNum, string reqType)
{
//On their side, every frame, the second player's X, Y, and Z pos should be packed into a string with seperator char '|' and then filed on the server under playerdata/2/pos/
//Then, this script(on the side of player 1) would(every frame, displaced by +1 frame initially) take the player number and the reqType to find said directory online with THIS function to return the value.
//Funny thing is; I have no idea what I'm doing.
//And no, I haven't connected to a server yet. I also want to stay away from any third party apps for this since this is small-scale and I only wish to learn the ins and outs of all of this.
}
void Update()
{
String p2Position = serverGet(2,"pos");
// String p2Position's value is currently "x|y|z"
String[] sl = p2Position.Split('|');
float xPos = float.parse(sl[0]);
float yPos = float.parse(sl[1]);
float zPos = float.parse(sl[2]);
// Now that all values are floats, we can feed them into the thingamabobber to change the position of the other player from our side.
p2Obj.transform.position = new Vector3(xPos, yPos, zPos);
}
}
Below I have a script which, if the serverGet() function's contents were actually existant(and functional, of course), would set the position of the second player to their position according to the data online, which the instance from their side submits in the first place(every frame as well, -1 frame initial displacement so that everything works). This way, if I move on one computer as "player 2", the computer in which I am playing as "player 1" will show the movement of player 2 as it progresses every frame. In other words, basically all calculation is client-side, but the actual communication is(unavoidably) server-side. That server-side is what I'm clueless about, and would appreciate if anyone here could lead me a step in the right direction.
As for the script that actually submits the terms to the server, that will come with my understanding of all of this; which again, I don't have as of right now.
There seems to have been a number of questions lately: "So I'm gonna write a MP game engine from scratch!" (Example.)
To get some basic grounding in mmp engineering, first spend a few days working with Unity's system https://docs-multiplayer.unity3d.com
Do try to understand the scale of your problem. You're about to embark on a PhD level enterprise that will take months of full-time work at the minimum. It would be insanity to not, first, spend a few days with current systems to gain some basic principles.
Similarly, Photon is very popular for mmp systems, https://www.raywenderlich.com/1142814-introduction-to-multiplayer-games-with-unity-and-photon next spend a few days making toy Photon/Unity systems to learn more.
Finally Mirror networking is the one that is "like Unity's old networking" https://assetstore.unity.com/packages/tools/network/mirror-129321 so really you should try that a little too.
Finally on the face of it to literally answer your question as is, click over to AWS, spin up some ubuntu EC2 instances, and start work on a "simple" game server, so almost certainly you'd use Node/Express/SQL and likely websockets (just to get started, you'd have to move to raw udp communications eventually). It's just not realistic to start doing that though until you familiarize yourself with some basic existing systems.
I'm using OxyPlot in my wpf application as line recorder. It's like the LiveDemo example.
On a larg visible data set, I get some UI performance issues and may the whole application could freez. It seems to be PlotModel.InvalidatePlot which is called with to many points to often, but I didn't found a better way.
In deep:
Using OxyPlot 2.0.0
I code all in the PlotModel. The Xaml PlotView is only binding to the PlotModel.
I cyclical collect data in a thread an put them in a DataSource (List of List which are ItemSoure for the LineSeries)
I have a class which calculates cyclical in a thread the presentation for x and y axis and a bit more. After all this stuff, it calls PlotModel.InvalidatePlot.
If I
have more than 100 k points on the display (no matter if in multiple LineSeries or not)
and add 1 DataPoint per LineSeries every 500 ms
and call PlotModel.InvalidatePlot every 200 ms
not only the PlotView has performance issues, also the window is very slow in reaction, even if I call PlotModel.InvalidatePlot (false).
My goal
My goal would be that the Windo / Application is working normally. It should not hang up because of a line recorder. The best would be if it has no performance issues, but I'm skeptical.
What I have found or tested
OxyPlot has Performance guidelines. I'm using ItemsSource with DataPoints. I have also tried adding them directly to the LineSeris.Points, but then the Plot doesn’t refresh anyway (even with an ObservableCollection), so I have to call PlotModel.InvalidatePlot, what results in the same effect. I cannot bind to a defined LineSeries in Xaml because I don’t know how much Lines will be there. Maybe I missed something on adding the points directly?
I have also found a Github issue 1286 which is describing a related problem, but this workaround is slower in my tests.
I have also checked the time which is elapsed on the call of PlotModel.InvalidatePlot, but the count of points does not affect it.
I have checked the UI thread and it seems it have trouble to handle this large set of points
If I zoom in to the plot and display under 20 k Points it looks so
Question:
Is there a way to handle this better, except to call PlotModel.InvalidatePlot much less?
Restrictions:
I also must Update Axis and Annotations. So, I think I will not come around to call PlotModel.InvalidatePlot.
I have found that using the OxyPlot Windows Forms implementation and then displaying it using Windows Form integration in WPF gives much better performance.
e.g.
var plotView = new OxyPlot.WindowsForms.PlotView();
plotView.Model = Plot;
var host = new System.Windows.Forms.Integration.WindowsFormsHost();
host.Child = plotView;
PlotContainer = host;
Where 'Plot' is the PlotModel you call InvalidatePlot() on.
And then in your XAML:
<ContentControl Content="{Binding PlotContainer}"/>
Or however else you want to use your WindowsFormsHost.
I have a similar problem and found that you can use a Decimator in LineSeries. It is documented in the examples: LineSeriesExamples.cs
The usage is like this:
public static PlotModel WithXDecimator()
{
var model = new PlotModel { Title = "LineSeries with X Decimator" };
var s1 = CreateSeriesSuitableForDecimation();
s1.Decimator = Decimator.Decimate;
model.Series.Add(s1);
return model;
}
This may solve the problem on my side, and I hope it helps others too. Unfortunately it is not documented in the documentation
For the moment I ended up with calculating the time for calling InvalidatePlot for the next time. I calculate it with the method given in this answer, wich returns the number of visible points. This rededuce the performance issue, but dosent fix the block on the UI Thread on calling InvalidatePlot.
I'm looking for a method to wait for the GPU to finish its work in DirectX9. Something equivalent to the glFinish command in OpenGL...
I already know that it's not something I should do, but I have to! I'm writing a threaded Graphics Engine integrated in WPF and I need to make sort of an off-screen rendering in order to give a valid surface to a D3DImage. The frames are very long to compute (more than 100ms) and the rendering of the WPF Image sometimes occurs while the frame is not fully computed by my Engine even if I lock everything the right way. I'm almost sure it's just a Finish issue but I didn't find out how to do that.
So far, I tried to launch a DX9 query like this :
using namespace SlimDX.Direct3D9;
public class GraphicsDevice: Device
{
...
public void Finish()
{
var query = new Query(this, QueryType.Event);
EndScene();
while (!query.CheckStatus(true)) ;
}
}
But it does not seem to work...
So, first question without talking about WPF, do you know how to wait for the GPU to finish what has been sent to the driver?
Thanks!
This was the solution.
I was not aware that it actually work!
I used an EventQuery to 'mark' my last call to the GPU.
Then I put some kind of infinite loop flushing the GPU instructions and waiting for the EventQuery to be finally fired by the GPU, using the GetData/CheckStatus methods.
I am using the SharpDX.WPF project for the WPF abilities, it seems like an easy to understand low-overhead library, compared to the Toolkit that comes with SharpDX (which has the same issue!)
First: I fixed the SharpDX.WPF project for the latest SharpDX using the following: https://stackoverflow.com/a/19791534/442833
Then I made the following hacky adjustment to DXElement.cs, a solution that was also done here:
private Query queryForCompletion;
public void Render()
{
if (Renderer == null || IsInDesignMode)
return;
var test = Renderer as D3D11;
if (queryForCompletion == null)
{
queryForCompletion = new Query(test.Device,
new QueryDescription {Type = QueryType.Event, Flags = QueryFlags.None});
}
Renderer.Render(GetDrawEventArgs());
Surface.Lock();
test.Device.ImmediateContext.End(queryForCompletion);
// wait until drawing completes
Bool completed;
var counter = 0;
while (!(test.Device.ImmediateContext.GetData(queryForCompletion, out completed)
&& completed))
{
Console.WriteLine("Yielding..." + ++counter);
Thread.Yield();
}
//Surface.Invalidate();
Surface.AddDirtyRect(new Int32Rect(0, 0, Surface.PixelWidth, Surface.PixelHeight));
Surface.Unlock();
}
Then I render 8000 cubes in a cube pattern...
Yielding...
gets printed to the console quite often, but the flickering is still there.
I am assuming that WPF is nice enough to show the image using a different thread before the rendering is done, not sure though...
This same issue also happens when I use the Toolkit variant of WPF support with SharpDX.
Images to demonstate the issue:
Bad
Better
Almost
Intended
Note: It randomly switches between these old images, randomly. I am also using really old hardware which makes the flickering much more appearant (GeForce Quadro FX 1700)
A made a repo which contains the exact same source-code as I am using to get this issue:
https://github.com/ManIkWeet/FlickeringIssue/
Related to D3DImage locking, note that the D3DImage.TryLock API has rather unconventional semantics which most developers would not expect:
Beware!
You must call Unlock even in the case where TryLock indicates failure (i.e., returns false)
Although perhaps more of an alarming design choice than a bug per se, misunderstanding this behavior will trivially result in D3DImage deadlocks and hangs, and thus might be responsible for much of the frustration people experience in attempting to get D3DImage working properly.
The following code is a correct WPF D3D render with no flicker in my app:
void WPF_D3D_render(IntPtr pSurface)
{
if (TryLock(new Duration(default(TimeSpan))))
{
SetBackBuffer(D3DResourceType.IDirect3DSurface9, pSurface);
AddDirtyRect(new Int32Rect(0, 0, PixelWidth, PixelHeight));
}
Unlock(); // <--- !
}
Yes, this unintuitive code is actually correct; it is the case that that D3DImage.TryLock(0) leaks one internal D3D buffer lock every time it returns failure. You don't have to take my word for it, here's the CLR code from PresentationCore.dll v4.0.30319:
private bool LockImpl(Duration timeout)
{
bool flag = false;
if (_lockCount == uint.MaxValue)
throw new InvalidOperationException();
if (_lockCount == 0)
{
if (timeout == Duration.Forever)
flag = _canWriteEvent.WaitOne();
else
flag = _canWriteEvent.WaitOne(timeout.TimeSpan, false);
UnsubscribeFromCommittingBatch();
}
_lockCount++;
return flag;
}
Notice that the internal _lockCount field is incremented regardless of whether the function returns success or failure. You have to call Unlock() yourself, as shown in the first code example above, if you want to avoid certain deadlock. Failing to do so creates is nasty to debug, too, because the component won't (potentially) deadlock until the next render pass, by which time the relevant evidence is long gone.
The unusual behavior does not seem to be mentioned at MSDN, but to be fair, that documentation doesn't note that you have to call Unlock() if the call is successful, either.
The problem is not the Locking mechanism. Normally you use Present to draw to present the image. Present will wait until all drawing is ready. With D3DImage you are not using the Present() method. Instead of Presenting, you lock, adding a DirtyRect and unlock the D3DImage.
The rendering is done asynchrone so when you are unlocking, the draw actions might not be ready. This is causing the flicker effect. Sometimes you see items half drawn. A poor solution (i've tested with) is adding a small delay before unlocking. It helped a little, but it wasn't a neat solution. It was terrible!
Solution:
I continued with something else; I was expirimenting with MSAA (antialiasing) and the first problem I faced was; MSAA cannot be done on the dx11/dx9 shared texture, so i decided to render to a new texture (dx11) and create a copy to the dx9 shared texture. I slammed my head on the tabel, because now it was anti-aliased AND flicking-free!! Don't forget to call Flush() before adding a dirty rect.
So, creating a copy of the texture: DXDevice11.Device.ImmediateContext.ResolveSubresource(_dx11RenderTexture, 0, _dx11BackpageTexture, 0, ColorFormat); (_dx11BackpageTexture is shared texture) will wait until the rendering is ready and will create a copy.
This is how I got rid of the flickering....
I think you are not locking properly. As far as I understand the MSDN documentation you are supposed to lock during the entire rendering not just at the end of it:
While the D3DImage is locked, your application can also render to the Direct3D surface assigned to the back buffer.
The information you find on the net about D3DImage/SharpDX is somewhat confusing because the SharpDX guys don't really like the way D3DImage is implemented (can't blame them), so there are statements about this being a "bug" on Microsofts side when its actually just improper usage of the API.
Yes, locking during rendering has performance issues, but it is probably not possible to fix them without porting WPF to DirectX11 and implementing something like a SwapChainPanel which is available in UWP apps. (WPF itself still runs on DirectX9)
If the locking is a performance issue for you, one idea I had (but never tested) is that you could render to an offscreen surface and reduce the lock duration to copying that surface over to the D3DImage. No idea if that would help performance wise but its something to try.
The classic advice in multithreading programing is to do processor heavy work on a background thread and return the result to the UI thread for minor processing (update a label, etc). What if generating the WPF element itself is the operation which is expensive?
I'm working with a third party library which generates some intense elements, which can take around to 0.75s - 1.5s to render. Generating one isn't too bad, but when I need to create 5 of them to show at once it noticeably locks the UI (including progress spinners). Unfortunately, there isn't any other place to create them because WPF is thread affine.
I've already tried DispatcherPriority.Background but its not enough. What is the recommended way to deal with this problem?
If the objects being created derived from Freezable, then you can actually create them on a different thread than the UI thread - you just have to call Freeze on them while you're on the worker thread, and then you can transfer them over. However, that doesn't help you for items that don't derive from Freezable.
Have you tried creating them one at a time? The following example doesn't do any useful work but it does show how the basic structure for doing a lot of work in little bits:
int count = 100;
Action slow = null;
slow = delegate
{
Thread.Sleep(100);
count -= 1;
if (count > 0)
{
Dispatcher.BeginInvoke(slow, DispatcherPriority.Background);
}
};
Dispatcher.BeginInvoke(slow, DispatcherPriority.Background);
The 'work' here is to sleep for a tenth of a second. (So if you replace that with real work that takes about as long, you'll get the same behaviour.) This does that 100 times, so that's a total of 10 seconds of 'work'. The UI remains reasonably responsive for the whole time - things like dragging the window around become a bit less smooth, but it's perfectly usable. Change both those Background priorities to Normal, and the application locks up.
The key here is that we end up returning after doing each small bit of work having queued up the next bit - we end up calling Dispatcher.BeginInvoke 100 times in all instead of once. That gives the UI a chance to respond to input on a regular basis.