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  • Improving the efficiency of multiple concurrent Core Animation animations

    - by Alex
    I have a view in my app that is very similar to the month view in the built-in Calendar app. There's a subview that holds the individual cells (a custom UIView subclass that draws text into its layer), and when the user navigates to the next "month", I create the new cells and slide the view to show them. When the animation stops, I remove the old, hidden cells and set things up so it's ready to go for the next animation. This all works nicely. However, I'd like to animate the cells' text color, as in the Calendar app, so that the outgoing ones transition to a lighter color and the incoming ones transition to a darker color. The problems is that I can have as many as 70 cells, so doing individual animations is very slow -- between 5-10 fps on my iPhone 3GS. I'm trying to find a less computationally intense way of doing this. My reading of the Shark results is that the majority of the time is spent redrawing the text for each frame for each frame. This makes sense, since text rendering is hardly the cheapest operation. I've considered creating a second view -- one holding the "outgoing" state and one holding the "incoming" state and using a single opacity animation to gradually reveal the updated cells while both are sliding. I'm concerned that instead of having 70 cells, I'll have 140, which seems like a lot of views. So, is that too many views or would there be a better way of doing this?

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  • Concurrent processes do not utilize all available CPU

    - by metdos
    I run some processes on an EC2 cc2.8xlarge instance which has 32 virtual processors. For some type of processes, when I run 16 processes on parallel, all of them use 100% of CPU cycles. But for other type of processes, they are not using 100% CPU and they finish considerably slower than a single thread. There is no time spend on IO and all data is served from memory. Do you have any idea about the reason of this problem?

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  • Why does java.util.concurrent.ArrayBlockingQueue use 'while' loops instead of 'if' around calls to

    - by theFunkyEngineer
    I have been playing with my own version of this, using 'if', and all seems to be working fine. Of course this will break down horribly if signalAll() is used instead of signal(), but if only one thread at a time is notified, how can this go wrong? Their code here - check out the put() and take() methods; a simpler and more-to-the-point implementation can be seen at the top of the JavaDoc for Condition. Relevant portion of my implementation below. public Object get() { lock.lock(); try { if( items.size() < 1 ) hasItems.await(); Object poppedValue = items.getLast(); items.removeLast(); hasSpace.signal(); return poppedValue; } catch (InterruptedException e) { e.printStackTrace(); return null; } finally { lock.unlock(); } } public void put(Object item) { lock.lock(); try { if( items.size() >= capacity ) hasSpace.await(); items.addFirst(item); hasItems.signal(); return; } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } P.S. I know that generally, particularly in lib classes like this, one should let the exceptions percolate up.

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  • How can an IBM WebSphere MQ's Queue Manager's local queues be enumerated?

    - by Jean-Paul Calderone
    I'm trying to write a simple tool for monitoring the state of a Queue Manager. One of the things I'd like to monitor is the current queue depth of each queue. I haven't been able to find a way to programmatically enumerate all of the queues on a particular Queue Manager, though. Do any of the MQ APIs provide this functionality? I'd prefer to do this with C, but if it's only possible with another language's bindings, I'd at least like to know that.

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  • Workaround the flip queue (AKA pre-rendered frames) in OpenGL?

    - by user41500
    It appears that some drivers implement a "flip queue" such that, even with vsync enabled, the first few calls to swap buffers return immediately (queuing those frames for later use). It is only after this queue is filled that buffer swaps will block to synchronize with vblank. This behavior is detrimental to my application. It creates latency. Does anyone know of a way to disable it or a workaround for dealing with it? The OpenGL Wiki on Swap Interval suggests a call to glFinish after the swap but I've had no such luck with that trick.

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  • jQuery multiple if else Statements

    - by Chris MMgr
    I have a set of images that I am trying to activate (change opacity) based on the position of a user's window. The below code works, but only through a long series of if else statements. Is there a way to shorten the below code? //Function to activate and deactivate the buttons on the side menu function navIndicator() { var winNow = $(window).scrollTop(); var posRoi = $('#roi').offset(); var posRoiNow = posRoi.top; //Activate the propper button corresponding to what section the user is viewing if (winNow == posRoiNow * 0) { $('#homeBut a img.active').stop().animate({ opacity: 1 } { queue: false, duration: 300, easing: "easeOutExpo" }); $('#homeBut').addClass("viewing") } else { $('#homeBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#homeBut').removeClass("viewing") } if (winNow == posRoiNow) { $('#roiBut a img.active').stop().animate({ opacity: 1 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#roiBut').addClass("viewing") } else { $('#roiBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#roiBut').removeClass("viewing") } if (winNow == posRoiNow * 2) { $('#dmsBut a img.active').stop().animate({ opacity: 1 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#dmsBut').addClass("viewing") } else { $('#dmsBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#dmsBut').removeClass("viewing") } if (winNow == posRoiNow * 3) { $('#techBut a img.active').stop().animate({ opacity: 1 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#techBut').addClass("viewing") } else { $('#techBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#techBut').removeClass("viewing") } if (winNow == posRoiNow * 4) { $('#impBut a img.active').stop().animate({ opacity: 1 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#impBut').addClass("viewing") } else { $('#impBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#impBut').removeClass("viewing") } if (winNow == posRoiNow * 5) { $('#virBut a img.active').stop().animate({ opacity: 1 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#virBut').addClass("viewing") } else { $('#virBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#virBut').removeClass("viewing") } if (winNow == posRoiNow * 6) { $('#biBut a img.active').stop().animate({ opacity: 1 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#biBut').addClass("viewing") } else { $('#biBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#biBut').removeClass("viewing") } if (winNow == posRoiNow * 7) { $('#contBut a img.active').stop().animate({ opacity: 1 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#contBut').addClass("viewing") } else { $('#contBut a img.active').stop().animate({ opacity: 0 }, { queue: false, duration: 300, easing: "easeOutExpo" }); $('#contBut').removeClass("viewing") } };

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  • Android Loading listview items from service results in hang

    - by Isaac Waller
    Hello, In my Android application, I have a ListActivity. This ListActivity uses a SimpleAdapter that I fill with items from my service. So, in my code, I do: MySuperCoolService.Binder serviceBinder = null; private ServiceConnection serviceConnection = new ServiceConnection() { public void onServiceConnected(ComponentName className, IBinder service) { Log.d(TAG, "Service connection: connected!"); serviceBinder = (MySuperCoolService.Binder)service; } public void onServiceDisconnected(ComponentName className) { Log.d(TAG, "Service connection: disconnected"); serviceBinder = null; } }; bindService(new Intent(this, MySuperCoolService.class), serviceConnection, BIND_AUTO_CREATE); while(serviceBinder==null) { Thread.Sleep(1000); } // now retrieve from service using binder and set list adapter This whole operation takes hardly any time (less than a second), so I want it to run in the UI thread. See my onCreate: public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); fillDataUsingCodeAbove(); } The reason I want this to run in the UI thread is that if you have a list item selected, or you have scrolled to a certain position in the ListView, and you rotate the device or take out the keyboard or something (to trigger a configuration change) when my activity is restarted, Android will try to restore the state right after onCreate. But, if I run it in a separate thread, it will not. Also there is a cool fadein animation too :) The problem I am having with running it in the UI thread is that when I try to bind to the service, that service bind request gets put onto the message queue. But then when I go into my loop, I stop the message queue from looping. So my program hangs, because it's waiting for the service to get bound, and the service won't get bound until the loop ends. I have thought of putting Looper.loop() inside my loop, but that just hangs it at Looper.loop() (I don't know why.) Sorry for such a long question, Isaac Waller

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  • Recycle Freed Objects

    - by uray
    suppose I need to allocate and delete object on heap frequently (of arbitrary size), is there any performance benefit if instead of deleting those objects, I will return it back to some "pool" to be reused later? would it give benefit by reduce heap allocation/deallocation?, or it will be slower compared to memory allocator performance, since the "pool" need to manage a dynamic collection of pointers. my use case: suppose I create a queue container based on linked list, and each node of that list are allocated on the heap, so every call to push() and pop() will allocate and deallocate that node: ` template <typename T> struct QueueNode { QueueNode<T>* next; T object; } template <typename T> class Queue { void push(T object) { QueueNode<T>* newNode = QueueNodePool<T>::get(); //get recycled node if(!newNode) { newNode = new QueueNode<T>(object); } // push newNode routine here.. } T pop() { //pop routine here... QueueNodePool<T>::store(unusedNode); //recycle node return unusedNode->object; } } `

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  • Best practices for (over)using Azure queues

    - by John
    Hi, I'm in the early phases of designing an Azure-based application. One of the things that attracts me to Azure is the scalability, given the variability of the demand I'm likely to expect. As such I'm trying to keep things loosely coupled so I can add instances when I need to. The recommendations I've seen for architecting an application for Azure include keeping web role logic to a minimum, and having processing done in worker roles, using queues to communicate and some sort of back-end store like SQL Azure or Azure Tables. This seems like a good idea to me as I can scale up either or both parts of the application without any issue. However I'm curious if there are any best practices (or if anyone has any experiences) for when it's best to just have the web role talk directly to the data store vs. sending data by the queue? I'm thinking of the case where I have a simple insert to do from the web role - while I could set this up as a message, send it on the queue, and have a worker role pick it up and do the insert, it seems like a lot of double-handling. However I also appreciate that it may be the case that this is better in the long run, in case the web role gets overwhelmed or more complex logic ends up being required for the insert. I realise this might be a case where the answer is "it depends entirely on the situation, check your perf metrics" - but if anyone has any thoughts I'd be very appreciative! Thanks John

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  • Consequent attribute calculations with a queuing system

    - by vrinek
    For all of the following assume these: rails v3.0 ruby v1.9 resque We have 3 models: Product belongs_to :sku, belongs_to :category Sku has_many :products, belongs_to :category Category has_many :products, has_many :skus When we update the product (let's say we disable it) we need to have some things happen to the relevant sku and category. The same is true for when a sku is updated. The proper way of achieving this is have an after_save on each model that triggers the other models' update events. example: products.each(&:disable!) # after_save triggers self.sku.products_updated # and self.category.products_updated (self is product) Now if we have 5000 products we are in for a treat. The same category might get updated hundreds of times and hog the database while doing so. We also have a nice queueing system, so the more realisting way of updating products would be products.each(&:queue_disable!) which would simply toss 5000 new tasks to the working queue. The problem of 5000 category updates still exists though. Is there a way to avoid all those updates on the db? How can we concatenate all the category.products_updated for each category in the queue?

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  • How to read from multiple queues in real-world?

    - by Leon Cullens
    Here's a theoretical question: When I'm building an application using message queueing, I'm going to need multiple queues support different data types for different purposes. Let's assume I have 20 queues (e.g. one to create new users, one to process new orders, one to edit user settings, etc.). I'm going to deploy this to Windows Azure using the 'minimum' of 1 web role and 1 worker role. How does one read from all those 20 queues in a proper way? This is what I had in mind, but I have little or no real-world practical experience with this: Create a class that spawns 20 threads in the worker role 'main' class. Let each of these threads execute a method to poll a different queue, and let all those threads sleep between each poll (of course with a back-off mechanism that increases the sleep time). This leads to have 20 threads (or 21?), and 20 queues that are being actively polled, resulting in a lot of wasted messages (each time you poll an empty queue it's being billed as a message). How do you solve this problem?

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  • Parallel programming patterns for C#?

    - by VoidDweller
    With Intel's launch of a Hexa-Core processor for the desktop, it looks like we can no longer wait for Microsoft to make many-core programming "easy". I just order a copy of Joe Duffy's book Concurrent Programming on Windows. This looks like a great place to start, though, I am hoping some of you who have been targeting multi/many core systems would point me to some good resources that have or would have helped on your projects?

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  • How to connect to local MQseries queue using Python?

    - by Michal Niklas
    I am new to mqseries and I started with IBM WebSphere MQ curses. There are examples with MQ_APPLE and MQ_ORANGE queue managers. I have no problem with sending messages to local or remote queue with MQ Explorer, but I wanted to send such message from code: Python or Java. I tried Python pymqi library with code like this: import pymqi qmgr = pymqi.QueueManager(None) qmgr.connect('QM_APPLE') putq = pymqi.Queue(qmgr, 'Q1') putq.put('Hello from Python!') but I receive error: Traceback (most recent call last): File "mq_put.py", line 4, in <module> qmgr.connect('QM_APPLE') File "c:\Python26\lib\site-packages\pymqi.py", line 758, in connect raise MQMIError(rv[1], rv[2]) pymqi.MQMIError: MQI Error. Comp: 2, Reason 2540: FAILED: MQRC_UNKNOWN_CHANNEL_NAME There is QM_APPLE queue manager with Q1 local queue. What is wrong with my code?

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  • How to learn about Threads, Especially in Java.

    - by Javed Ahamed
    I have always been kind of confused by threads, and my class right now makes heavy use of them. We are using java.util.concurrent but I don't even really get the basics. UpDownLatch, Futures, Executors; these words just fly over my head. Can you guys suggest any resources to help learn what I need from the ground up? Thanks a lot in advance!

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  • What is the best way to reject messages with the same body in AMQ queue?

    - by archer
    I have a single AMQ queue that receives simple messages with string body. Consider I'm sending CLSIDs as message bodies. CLSIDs could be not unique, but I'd like to reject all messages with not unique bodies and keep only single instance of such messages in the queue. Is there any simple way to do it? Currently I'm using a workaround. Messages from the queue are consumed by some processor that tries to insert bodies into a simple DB table with UNIQUE constraint applied to message_body field. If processor inserts the messages succesfuly - it's assigned to exchange.out.body and sent to other queue. If ConstraintViolationException is thrown - nothing is resent to other queue. I would like to know does AMQ support something similar out of the box?

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  • PriorityQueue update problems

    - by Bharat
    After going through a bunch of questions here on SO, I still have no idea what exactly is going wrong with my code and would appreciate some help. I'm trying to implement a priority queue based on f-costs for an A* algorithm, and while the algorithm works fine for short pathfinding distances, it seems to go wrong when there's an obstacle or when the distance between start and goal points is greater than about 30 squares (although sometimes it screws up for less too). while(!m_qOpenList.isEmpty()) { m_xCurrent=m_qOpenList.poll(); m_xCurrent.setBackground(Color.red); m_qClosedList.add(m_xCurrent); if(m_xCurrent.getStatus()==2) { System.out.println("Target Reached"); solved=true; break; } iX=m_xCurrent.getXCo(); iY=m_xCurrent.getYCo(); for(i=iX-1;i<=iX+1;i++) for(j=iY-1;j<=iY+1;j++) { if(i<0||j<0||i>m_iMazeX||j>m_iMazeX||(i==iX&&j==iY) || m_xNode[i][j].getStatus()==4|| m_qClosedList.contains(m_xNode[i][j])) continue; m_xNode[i][j].score(m_xCurrent,m_xGoal); m_qOpenList.add(m_xNode[i][j]); } } It's quite rudimentary as I'm just trying to get it to work for now. m_qOpenList is the PriorityQueue. The problem is that when I debug the program, at some point (near an obstacle), a Node with a fcost of say 84 has higher priority than a node with an fcost of 70. I am not attempting to modify the values once they're on the priority queue. You'll notice that I add at the end of the while loop (I read somewhere that the priorityqueue reorders itself when stuff is added to it), and poll right after that at the beginning. Status of 2 means the Node is the goal, and a status of 4 means that it is unwalkable. public int compareTo(Node o) { if(m_iF<o.m_iF) return -1; if(m_iF>o.m_iF) return 1; return 0; } And that's the compareTo function. Can you see a problem? =(

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  • Check for messages apache Qpid

    - by c0mrade
    Is it possible to check for messages from Qpid queue from unix/windows console? Here is how I check via GUI : http://i47.tinypic.com/pbu5d.gif I can see all the info from Qpid JMX Management Console, is there a something close to this that I can use in console?

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  • Conflating queues

    - by oo
    Are there any good examples of conflating queue in dotnet. I have thousands of messages per second coming in from another system and i wanted to see if this was the best solution and see some implementation examples

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  • Carrot (Python) [errno 10054] An existing connection was forcibly closed by the remote host

    - by Meditation
    Hi all, We are using Carrot in our Python project. I wrote a Python script acting as the consumer of the message queue. I invoked this Python script using command line shell in Windows 7 as python consumer.py However, after a while, the running session was aborted and the error is: [errno 10054] An existing connection was forcibly closed by the remote host The producer session is still running fine on the Linux server. Just wondering how can I fix this and have a long running consumer session on Windows Thanks in advance.

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  • persistant message queues

    - by Will
    I have several services on different machines and a message-passing system suits my problem. Reliability - sent messages always delivered, even if one end goes down - is the key concern, although it should also be fast and reasonably bandwidth-efficient. So which message queue should I use?

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  • Multiple Queues in jQuery

    - by kingjeffrey
    I am having problems using multiple queues in jQuery. Consider the following example: $('#example').click(function() { $(this).delay(1000, 'fx2').queue('fx2', function() { alert('here'); }); }); The alert never fires. Why?

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