memory-management

问题 If a variable is assigned any new content, will the memory allocated for the "old content" be "properly" free'd? For example, in the following script, will the memory for variable "a" as an array of zeros be free'd after "a" is assigned some new stuff import numpy a = numpy.zeros(1000) a = a+1 I would imaging Python is smart enough to do everything cleanly, using the so-called 'garbage collection', which I never really be able to read through. Any confirmation? I'd appreciate it. 回答1:

问题 I want to know if a program that I am using and which requires a lot of memory is limited by the memory bandwidth. When do you expect this to happen? Did it ever happen to you in a real-life scenario? I found several articles discussing this issue, including: http://www.cs.virginia.edu/~mccalpin/papers/bandwidth/node12.html http://www.cs.virginia.edu/~mccalpin/papers/bandwidth/node13.html http://ispass.org/ucas5/session2_3_ibm.pdf The first link is a bit old, but suggests that you need to

问题 I am working on this c program. I am compiling it with gcc on a 64 bits x64 linux: #include <stdio.h> char buffer[]={0x90,0x90,0xC3}; int main(int argc, char *argv[]) { void (*fct)(); fct=buffer; fct(); return 0; } 0x90 opcode is NOP 0xC3 opcode is RET I want to know what i should do in order to run this program. I get a segfault when running it... Thanks 回答1: TL;DR Compile with -z execstack to enable Linux's read-implies-exec feature for your executable. Despite the name, it applies to all

问题 I am working on this c program. I am compiling it with gcc on a 64 bits x64 linux: #include <stdio.h> char buffer[]={0x90,0x90,0xC3}; int main(int argc, char *argv[]) { void (*fct)(); fct=buffer; fct(); return 0; } 0x90 opcode is NOP 0xC3 opcode is RET I want to know what i should do in order to run this program. I get a segfault when running it... Thanks 回答1: TL;DR Compile with -z execstack to enable Linux's read-implies-exec feature for your executable. Despite the name, it applies to all

问题 first of all i already had a look at several questions which are quite similar. But i wasn't able to find a solution. My script performs a load test it calls several different URLs(GET http) to download the content behind. After 120 requests the memory usage increases up to 2GB and after 500 to 5-6GB I changed already the xmx size in hope that this will solve the problem but it doesn't. Is there any way to configure jmeter to not save the files coming from a response? Or lets say to discard

问题 first of all i already had a look at several questions which are quite similar. But i wasn't able to find a solution. My script performs a load test it calls several different URLs(GET http) to download the content behind. After 120 requests the memory usage increases up to 2GB and after 500 to 5-6GB I changed already the xmx size in hope that this will solve the problem but it doesn't. Is there any way to configure jmeter to not save the files coming from a response? Or lets say to discard

问题 I'm doing some tests with 'malloc_stats' function and I've seen a strange behavior that I don't understand. The test is very easy, what I'm doing is allocate memory and print the 'malloc_stats' before the allocation, after the allocation and after free the memory. This is the code I'm using: int main(int argc, char *argv[]) { char *alloc[MAX_ALLOCS]; if ( argc < 3 or strcmp(argv[1], "--help") == 0 ) { cout << argv[0] << " num-blocks block-size [free-step [start-free [end-free]]]" << endl;

问题 malloc() returns a memory suitably aligned for any in-built type. In cases where more specific alignment is required (like 16 or 32 bytes) it can be done at the application level. But this alignment is at the virtual memory level. How is it guaranteed that the underlying physical memory is also at the same alignment ? 回答1: Virtual memory is implemented at the page level, so every VM page maps to a physical memory page when it's loaded into memory. So everything more finely grained than the

问题 I’m using SwfitUI in my project and I have a NavigationView and List. I’m clicking cell after open the detail view and click navigation back button. I want to remove view (it’s struct, in SwiftUI) after click navigation back button. Because if I click the same cell or button again, it isn’t initialize new view, it’s shows old view. I want to do refresh this view. How do I do? My FirstView Struct is: struct FirstView: View { @ObservedObject var viewModel: FirstViewModel var body: some View {

问题 In chapter 11 of Accelerated C++, the authors present a Vector class emulating the behaviour of std::vector using arrays. They use the allocator class to handle memory management. The role of the uncreate function is to destroy each element of the array and deallocate the space allocated for the array: template <class T> void Vec<T>::uncreate() { if (data) { // destroy (in reverse order) the elements that were constructed iterator it = avail; while (it != data) alloc.destroy(--it); // return