I recently started deploying my test code onto an actual device and ran some sample code provided by Xamarin involving different technologies that they introduce you to. Then I came upon an issue with their garbage collector when trying to test out sensors. With the latest version it runs when you reach a certain threshold however that makes the device unresponsive. Using the code from http://docs.xamarin.com/android/recipes/OS%2f%2fDevice_Resources/Accelerometer/Get_Accelerometer_Readings but just changing it to add 2 more sensors, a gyroscope and gravity sensors, the project lasts about 30 seconds before the GC begins to run. I noticed that every time you reference the e.Values list from the OnSensorChanged function you get more references created. Is there a way to delete those references, as the app I'm working on requires those three sensors and needs to run for about 4 to 5 mins, (its just a section of the app but a really important section). Thanks in advance for any help you can give me.
The following link actually provides a way to understand that issue comes up as well as the solution that would fix the issue completely.
https://bugzilla.xamarin.com/show_bug.cgi?id=1084#c6
Related
I am having a big problem with meteor. Build process "meteor run" is extremely slow it takes about 10 minutes but that is not the bad part since it only happens once when starting.
The bad part is that it takes ~2 minutes to show my changes, file changed watcher taking too long.
When working with a basic example the feedback was way better ~5 seconds and it was workable but now that I am working on a real project it is impossible to make any progress.
I have around 40 packages in packages file and I am using latest meteor (1.3.2.4 at this time).
There were a ton of questions around this problem #4284 #6750, I don't know if there is any tip to bypass this issue ( changing any config,adding more RAM or anything ).
It there is no solution of that it would be helpful if there is a way to limit file watch to only a certain folder at a moment.
Update: I noticed there is ".node_modules" in the root of app can it be excluded from build process?
Thank you guys!
Try Webpack for Meteor.
It supports hot module reload, which can shorten rebuild times a lot. There are some differences compared to the default build process, so you'll need to learn a thing or two about it, but it could be well worth your time.
Try it by fetching kickstart-meteor-react-flowrouter from GitHub.
I am not sure if I am posting to the right StackOverFlow forum but here goes.
I have a C# desktop app. It receives images from 4 analogue cameras and it tries to detect motion and if so it saves it.
When I leave the app running say over a 24hr cycle I notice the Private Working Set has climbed by almost 500% in Task manager.
Now, I know using Task Manager is not a good idea but it does give me an indication if something is wrong.
To that end I purchase dotMemory profiler from JetBrains.
I have used its tools to determine that the Heap Generation 2 increases a lot in size. Then to a lesser degree the Large Object Heap as well.
The latter is a surprise as the image size is 360x238 and the byte array size is always less than 20K.
So, my issues are:
Should I explicitly call GC.Collect(2) for instance?
Should I be worried that my app is somehow responsible for this?
Andrew, my recommendation is to take memory snapshot in dotMemory, than explore it to find what retains most of the memory. This video will help you. If you not sure about GC.Collect, you can just tap "Force GC" button it will collect all available garbage in your app.
I have posted on this before, but thought I had tracked it down to the NW extension, however, memory leakage still occurs in the latest version. I found this thread, which discusses a similar issues, but attributes it to Behavior Space:
http://netlogo-users.18673.x6.nabble.com/Behaviorspace-Memory-Leak-td5003468.html
I have found the same symptoms. My model starts out at around 650mb, but over each run the private working set memory rises, to the point where it hits the 1024 limit. I have sufficient memory to raise this, but in reality it will only delay the onset. I am using the table output, as based on previous discussions this helps, and it does, but it only slows the rate of increase. However, eventually the memory usage rises to a point where the PC starts to struggle. I am clearing all data between runs so there should be no hangover. I noticed in the highlighted thread that they were going to run headless. I will try this, but I wondered if anyone else had noticed the issue? My other option is to break the BehSpc simulation into a few batches so the issues never arises, bit i would be nice to let the model run and walk away as it takes around 2 hours to go through.
Some possible next steps:
1) Isolate the exact conditions under which the problem does or not occur. Can you make it happen without involving the nw extension, or not? Does it still happen if you remove some of the code from your model? What if you keep removing code — when does the problem go away? What is the smallest code that still causes the problem? Almost any bug can be demonstrated with only a small amount of code — and finding that smallest demonstration is exactly what is needed in order to track down the cause and fix it.
2) Use standard memory profiling tools for the JVM to see what kind of objects are using the memory. This might provide some clues to possible causes.
In general, we are not receiving other bug reports from users along these lines. It's routine, and has been for many years now, for people to use BehaviorSpace (both headless and not) and do experiments that last for hours or even for days. So whatever it is you're experiencing almost certainly has a more specific cause -- mostly likely, in the nw extension -- that could be isolated.
When I test my app directly on the device, it crashes because I'm attempting to JIT-compile a method. I know why these crashes occur, I'm just trying to make them appear when I'm testing on the simulator instead. It's much easier than deploying to a device every time (it also takes less time).
I tried adding --aot-only to the mtouch arguments but I get the "Unknown command line argument" error.
No, there's no AOT compiler shipped for x86.
Now even if there was one it would:
a) become a lot slower to build. In fact it would be similar to building for devices. The only time saved would be for deployment (which is not the largest part of the build/deploy time);
b) still give you different results than iOS devices. The iOS simulator is, in many ways, different than iOS devices so testing on devices is very important.
Notes:
A lot of the JIT exceptions are related to the use of value-types inside generics. This is being, in large part, fixed in the 6.3.x releases (beta);
There are tricks to make your device builds faster. You can find some here in stackoverflow and (soon) the video about my Evolve 2013 presentation should be available.
Environment
Windows XP SP3 x32
Visual Studio 2005 Standard Edition
Honeywell Dolphin 9500 Pocket PC/Windows Mobile 2003 Platform
Using the provided Honeywell Dolphin 9500 VS2005 SDK
.NET Framework 1.1 and .NET Compact Framework 1.0 SP3
Using VC#
Problem
When I save an image from the built in camera and Honeywell SDK ImageControl to the device's storage card or internal memory, it takes 6 - 7 seconds.
I am currently saving the image as a PNG but have the option of a BMP or JPG as well.
Relevant lines in the code: 144-184 and 222, specifically 162,163 and 222.
Goal
I would like to reduce that time down to something like 2 or 3 seconds, and even less if possible.
As a secondary goal, I am looking for a profiling suite for Pocket PC 2003 devices specifically supporting the .NET Compact Framework Version 1.0. Ideally free but an unfettered short tutorial would work as well.
Things I Have Tried
I looked into asynchronous I/O via System.Threading a little bit but I do not have the experience to know whether this is a good idea, nor exactly how to implement threading for a single operation.
With threading implemented as it is in the code below, there seems to be a trivial speed increase of maybe a second or less. However, something on the next Form requires the image, possibly in the act of being saved, and I do not know how to mitigate the wait or handle that scenario at all, really.
EDIT: Changing the save format from PNG to BMP or JPG, with the threading, seems to reduce the save time considerably..
Code
http://friendpaste.com/3J1d5acHO3lTlDNTz7LQzB
Let me know if the code should just be posted here in code tags. It is a little long (~226 lines) so I went ahead and friendpasted it as that seemed to be acceptable in my last post.
By changing the save format from PNG to BMP and including the Threading code shown in the Code link, I was able to reduce the save time to ~1 second.
You're at the mercy of the Honeywell SDK for this one, since their control is doing the actual saving of the image. Calling this on a separate thread (i.e. not the UI thread) isn't going to help at all (as you've found out), and it will actually make things more difficult for you since you need to wait until the save task is completed before moving on to the next form.
The only suggestion I can make is to make sure you're saving the image to internal memory (and not to the SD card), since writing to an SD card usually takes significantly longer than writing to memory. Or see if you can get technical support from Honeywell - 6-7 seconds seems way too long for a task like this.
Or see if the Honeywell SDK lets you get the image as a byte array (instead of saving to disk). If this call returns in less than 6-7 seconds, you can handle persisting it yourself.