memory-fragmentation

“Memory Fragmentation” is it still an issue? [closed]

由 三世轮回 提交于 2020-01-13 09:35:10
问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 2 years ago . I'm a little bit confused. In the OS course we were told that all OSes take care of memory fragmentation by paging or segmentation and there is no contiguous physical memory allocation at all. OS uses different levels of addressing (logical/physical) to avoid the contiguous memory

Linux: how to check the largest contiguous address range available to a process

由 自作多情 提交于 2019-12-21 20:58:02
问题 I want to enter the pid at the command line and get back the largest contiguous address space that has not been reserved. Any ideas? Our 32 bit app, running on 64 bit RHEL 5.4, craps out after running for a while, say 24 hours. At that time it is only up to 2.5 gb of memory use, but we get out of memory errors. We think it failing to mmap large files because the app's memory space is fragmented. I wanted to go out to the production servers and just test that theory. 回答1: Slighly nicer version

.NET application memory usage - high unused .NET and unmanaged memory and fragmentation

由 淺唱寂寞╮ 提交于 2019-12-21 17:02:34
问题 I am using ANTS memory profiler to diagnose an increase in memory leak I am facing in one of my .NET 2.0 applications. I took 7 snapshots of the process over a period of 7.5 hours, and here is a tabular representation of the data obtained - G1 reprsents generation 1 size and G2 generation 2 size. Except for the unmanaged space and private bytes, all other values are in MB. My questions are - Why is there such high unused .NET space even when the heap sizes are low ? My large object heap goes

Memory Fragmentation in C++

由 拈花ヽ惹草 提交于 2019-12-14 03:28:18
问题 I want to use malloc()/new to allocate 256KB memory to variable m. Then, use m to store data such as strings and numbers. My problem is how to save data to m and retrive them. For example, how to store int 123456 in offsets 0 to 3 and read it to variable x? Or store "David" string from offset 4 to 8(or 9 with \0) and then, retrive it to variable s? 回答1: You can store an integer by casting pointers. unsigned char *p = new unsigned char[256 * 1000]; *(int *) p = 123456; int x = *(int *) p; This

How do I measure fragmentation in Hotspot's Metaspace?

由 旧城冷巷雨未停 提交于 2019-12-11 03:48:49
问题 I'm looking into debugging an "OutOfMemoryError: Metaspace" error in my application. Right before the OOME I see the following in the gc logs: {Heap before GC invocations=6104 (full 39): par new generation total 943744K, used 0K [...) eden space 838912K, 0% used [...) from space 104832K, 0% used [...) to space 104832K, 0% used [...) concurrent mark-sweep generation total 2097152K, used 624109K [...) Metaspace used 352638K, capacity 487488K, committed 786432K, reserved 1775616K class space

What algorithm to apply for continuious reallocation of small memory chunks?

由 走远了吗. 提交于 2019-12-10 23:50:02
问题 In C program I face transactions that require to have alot of memory chunks, I need to know if there is an algorithm or best practice teqnique used to handle all these malloc/free, I've used arrays to store these memory chunks but at some point the array itself gets full and reallocating the array is just more waste, what is the elegant way to handle this issue? 回答1: The best algorithm in this case would be free list allocator + binary search tree. You are asking one big memory chunk from

“Memory Fragmentation” is it still an issue? [closed]

由 霸气de小男生 提交于 2019-12-05 07:18:06
I'm a little bit confused. In the OS course we were told that all OSes take care of memory fragmentation by paging or segmentation and there is no contiguous physical memory allocation at all. OS uses different levels of addressing (logical/physical) to avoid the contiguous memory allocation. Now here there are so many discussions about it. My question is: Is this problem real in c++ programming for OSes supporting logical addressing (does any process crash just because of memory fragmentation)? if yes, why in the first place each OS tries to avoid contiguous addressing? There are 2 layers:

Linux: how to check the largest contiguous address range available to a process

由 天大地大妈咪最大 提交于 2019-12-04 16:55:53
I want to enter the pid at the command line and get back the largest contiguous address space that has not been reserved. Any ideas? Our 32 bit app, running on 64 bit RHEL 5.4, craps out after running for a while, say 24 hours. At that time it is only up to 2.5 gb of memory use, but we get out of memory errors. We think it failing to mmap large files because the app's memory space is fragmented. I wanted to go out to the production servers and just test that theory. Slighly nicer version of my above comment: #!perl -T use warnings; use strict; scalar(@ARGV) > 0 or die "Use: $0 <pid>"; my $pid

.NET application memory usage - high unused .NET and unmanaged memory and fragmentation

由 前提是你 提交于 2019-12-04 06:59:59
I am using ANTS memory profiler to diagnose an increase in memory leak I am facing in one of my .NET 2.0 applications. I took 7 snapshots of the process over a period of 7.5 hours, and here is a tabular representation of the data obtained - G1 reprsents generation 1 size and G2 generation 2 size. Except for the unmanaged space and private bytes, all other values are in MB. My questions are - Why is there such high unused .NET space even when the heap sizes are low ? My large object heap goes to a maximum of some 2 MB, and during the last 3 snapshots remains at 96 KB. Then why is there such

Heap fragmentation when using byte arrays

由 |▌冷眼眸甩不掉的悲伤 提交于 2019-12-03 11:22:03
问题 I have a C# 4.0 application (single producer/single consumer) which transfers huge amount of data in chunks. Although there's no new memory allocation I run out of memory after a while. I profiled memory using Redgate memory profiler and there are a lot of free memory there. It says free memory cannot be used because of fragmentation. I use a blocking collection as the buffer and byte arrays as the members: BlockingCollection<byte[]> segments = new BlockingCollection<byte[]>(8); // producer:
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