memory | 易学教程

Do iterators save memory in Python?

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问题 I don't quite understand how iterators have memory in Python. >>> l1 = [1, 2, 3, 4, 5, 6] >>> l2 = [2, 3, 4, 5, 6, 7] >>> iz = izip(l1, l2) We still require O(min(l1, l2)) memory as we need to load the lists l1 and l2 in memory. I thought one of the main uses of iterators was to save memory - yet it does not seem to be useful here. Similarly, the code below is unclear to me: >>> l1 = ( n for n in [1, 2, 3, 4, 5, 6] ) >>> l2 = ( n for n in [2, 3, 4, 5, 6, 7] ) >>> iz = izip(l1, l2) We need to

My (huge) application throws an OutOfMemoryException, now what?

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问题 This is by far the most complex software I've built and now it seems to be running out of memory at some point. I haven't done extensive testing yet, because I'm a bit lost how I should approach the problem at hand. HandleCount: 277 NonpagedSystemMemorySize: 48136 PagedMemorySize: 1898590208 PagedSystemMemorySize: 189036 PeakPagedMemorySize: 1938321408 VirtualMemorySize: 2016473088 PeakVirtualMemory: 2053062656 WorkingSet: 177774592 PeakWorkingSet: 883834880 PrivateMemorySize: 1898590208

Can unused data members be optimized out in C++

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问题 I have a C++ class which has a private unused char[] strictly to add padding to the class to prevent false sharing when the class is used in a shared array. My question is 2-fold: Can this data member be optimized out by the compiler in some circumstances? How can I silence the private field * not used warnings when I compile with -Wall ? Preferably, without explicitly silencing the warning as I still want to catch instances of this issue elsewhere. I wrote a little test to check for my

64bit Memory allocation

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问题 I've been asked to create a Delphi compatible dll in C++ to do simple 64bit memory management. The background is that the system in Delphi needs to allocate a lots of chunks of memory that would go well outside 32bit addressable space. The Delphi developer explained to me that he could not allocate memory with the Delphi commands available to him. He says that he can hold a 64bit address, so he just wants to call a function I provide to allocate the memory and return a 64bit pointer to him.

Do object references take up extra memory?

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问题 Lets say you have the following complex object: var object1 = .... // (something complexed) This takes up x amount of memory in your JS application. Now lets say you have some other objects that reference object1 : var otherObject = { something: true, value: 'yes', object: object1 }; var anotherObject = { color: '#FFF', object: object1 }; Have I tripled the amount of memory that object1 originally took up? Or do the references to object1 not add to the overhead of the memory used? I'm not

Address woes from Hacking: The Art of Exploitation [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I bought this book recently titled: Hacking: The Art of Exploitation (2nd Edition) and it's been bugging me so much lately. Anyway, with one of the examples, firstprog.c : #include <stdio.h> int main() { int i; for(i=0; i < 10; i++) { // Loop 10 times. printf("Hello, world!\n"); // put the string to the output.

Memory Increase in SpriteKit even though removeAllChildren called

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问题 I've been trying to fix a huge memory increase in SpriteKit for many weeks now but have found no solution. I have tried just about every method that I've come across online for managing memory in SK but am still having troubles. Here's my situation: I first present the SKScene "HomeScreen" and from there I am changing Page scenes with a UIButton in my View Controller like so: func nextPage(sender: UIButton) { pageNumber = pageNumber + 1 let switchPage = SKTransition.crossFadeWithDuration(3.0)

volatile和synchronized

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volatile是变量修饰符，而synchronized则是作用于代码,方法和变量。 int i1; int geti1() {return i1;} volatile int i2; int geti2() {return i2;} int i3; synchronized int geti3() {return i3;} 1.geti1()是得到储存在当前线程中i1的数值，而多个线程又多份i1变量的拷贝，这些i1可能不相同。（另一个线程可能已经改变了它线程内的i1值，而这个值可以和当前线程中的i1值不相同。）在JAVA内存模型的，有main memory（主内存区域），存放着变量当前的准确值，每个线程也有自己的memory（例如寄存器），为了性能，一个线程会在自己的memory中保存要访问的变量的副本。这样就会出现同一个变量在某个瞬间，在一个线程的memory中的值可能与另外一个线程memory的值，或者main memory的值不一致的情况。因此实际上存在一种可能：main memory的值i1值是1，线程1里的i1是2，线程2里的i1值是3，这在线程1和线程2都改变了他们各自的i1值，而且这个改变还没来得及传给main memory 或其他线程时就会发生。 2.geti2() 得到的是main memory的i2数值。一个变量声明为volatile

Tomcat Fix Memory Leak?

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问题 I am using 6.0.20 I have a number of web apps running on the server, over time, approximately 3 days and the server needs restarting otherwise the server crashes and becomes unresponsive. I have the following settings for the JVM: -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=c:\tomcat\Websites\private\mydomain\apache-tomcat-6.0.20\logs This provides me with a hprof file which I have loaded using Java VisualVM which identifies the following: byte[] 37,206 Instances | Size 86,508,978 int[]

What's the difference between a memory arena and a memory allocator?

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问题 This is more a semantic question than a coding question.... What's the difference between a memory arena and a memory allocator? I'm working in C++ and I'm seeing some memory management libs using concepts like "memory arena", "memory allocator" and sometimes both in the same lib. I know what an allocator is; I'm just not sure what a memory arena is if it's not just another word for allocator. 回答1: "Memory arena" typically means a large lump (or collection of lumps) of memory from which