C++ memory profiler
I couldn't find any free c++ profiler with good interface for vs2005 running on 32bit winxp sp3. is there any free? ...
memory
Java: How ArrayList manages memory
In my Data Structures class we have studies the Java ArrayList class, and how it grows the underlying array when a user adds more elements. That is understood. However, I cannot figure out how exactly this class frees up memory when lots of elements are removed from the list. Looking at the source, there are three methods that remove ele...
How to change size of STL container in C++
I have a piece of performance critical code written with pointers and dynamic memory. I would like to rewrite it with STL containers, but I'm a bit concerned with performance. Is there a way to increase the size of a container without initializing the data? For example, instead of doing ptr = new BYTE[x]; I want to do something like...
how does memory stacks work in javascript
When we have code like: function a(){ var x =0; this.add=function(){ alert(x++); } } var test = new a(); test.add(); // alert 0 test.add(); // alert 1 test.add(); // alert 2 How does this work? Doesn't that the value of 'x' in a() should be 'gone' as soon as test = new a() is complete? The stack contains x shoul...
How is inheritance implemented at the memory level?
Suppose I have class A { public: void print(){cout<<"A"; }}; class B: public A { public: void print(){cout<<"B"; }}; class C: public A { }; How is inheritance implemented at the memory level? Does C copy print() code to itself or does it have a pointer to the it that points somewhere in A p...
Python Django Global Variables
Hi all, I'm looking for simple but recommended way in Django to store a variable in memory only. When Apache restarts or the Django development server restarts, the variable is reset back to 0. More specifically, I want to count how many times a particular action takes place on each model instance (database record), but for performan...
Mapping of memory addresses to physical modules in Windows XP
I plan to run 32-bit Windows XP on a workstation with dual processors, based on Intel's Nehalem microarchitecture, and triple channel RAM. Even though XP is limited to 4 GB of RAM, my understanding is that it will function with more than 4 GB installed, but will only expose 4 GB (or slightly less). My question is: Assuming that 6 GB of ...
Simple question on 8086 assembly language
I'm studying 8086 assembly language at high school and I have this question: For example I have this number ABCD (hex). How is it stored on the memory? Does the AB go for example to memory address 01 and the CD goes to address 02? ...
What is the difference between a segmentation fault and a stack overflow?
For example when we call say, a recursive function, the successive calls are stored in the stack. However, due to an error if it goes on infinitely the error is 'Segmentation fault' (as seen on GCC). Shouldn't it have been 'stack-overflow'? What then is the basic difference between the two? Btw, an explanation would be more helpful t...
Memory randomization as application security enhancement?
I recently came upon a Microsoft article that touted new "defensive enhancements" of Windows 7. Specifically: Address space layout randomization (ASLR) Heap randomization Stack randomization The article went on to say that "...some of these defenses are in the core operating system, and the Microsoft Visual C++ compiler offers o...
Approximate timings for various operations on a "typical desktop PC" anno 2010
In the article "Teach Yourself Programming in Ten Years" Peter Norvig (Director of Research, Google) gives the following approximate timings for various operations on a typical 1GHz PC back in 2001: execute single instruction = 1 nanosec = (1/1,000,000,000) sec fetch word from L1 cache memory = 2 nanosec fetch word from main memory = 1...
gcc memory alignment pragma
hello. Does gcc have memory alignment pragma, akin #pragma vector aligned in Intel compiler? I would like to tell compiler to optimize particular loop using aligned loads/store instructions. to avoid possible confusion, this is not about struct packing. e.g: #if defined (__INTEL_COMPILER) #pragma vector aligned #endif for (in...
Why exactly should I not call free() on variables not allocated by malloc()?
I read somewhere that it is disastrous to use free to get rid of an object not created by calling malloc, is this true? why? ...
How to measure the effect of correctly rebasing .NET assemblies before NGen?
Our application has a lot of .NET assemblies, which up until now, has not been deployed with NGen-scripts, so they are always JITted at runtime. Since our application is typically deployed to a terminal server, getting Windows to share binary images of the code is probably more optimal than the current way, so I'm looking at setting bas...
Objective-C memory management issue
I've created a graphing application that calls a web service. The user can zoom & move around the graph, and the program occasionally makes a decision to call the web service for more data accordingly. This is achieved by the following process: The graph has a render loop which constantly renders the graph, and some decision logic which...
Basic C++ Header File Question
Hi, I have a project with two header files mainwindow.h and website.h. I want to access a method from website.cpp from inside mainwindow.cpp. I can access any function from inside mainwindow by doing Window w then doing w->function(); However, when the function finishes from inside the mainwindow the memory for w is erased. How do...
Remove pointer object whose reference is mantained in three different lists
I am not sure how to approach this problem: 'Player' class mantains a list of Bullet* objects: class Player { protected: std::list< Bullet* > m_pBullet_list; } When the player fires a Bullet, it is added to this list. Also, inside the constructor of bullet, a reference of the same object is updated in CollisionMgr, where Collisio...
Browsers (IE and Firefox) freeze when copying large amount of text
I have a web application - a Java servlet - that delivers data to users in the form of a text printout in a browser (text marked up with HTML in order to display in the browser as we want it to). The text does display in different colors, though most of it is black. One typical mode of operation is this: 1. User submits a form to reque...
How to find number of memory accesses
Can anybody tell me a unix command that can be used to find the number of memory accesses that took place in a given interval. vmstat, top and sar only give the amount of physical memory space occupied/available .. But do not give the number of memory of accesses in a given interval ...
Objective-C NSDate memory issue (again)
I'm developing a graphing application and am attempting to change the renderer from OpenGL to Quartz2D to make text rendering easier. A retained NSDate object that was working fine before suddenly seems to be deallocating itself, causing a crash when an NSMutableString attempts to append it's decription (now 'nil'). Build & analyse doe...