In computing, memory refers to the state information of a computing system, as it is kept active in some physical structure.

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How can I observe memory bandwidth?

I have an embedded Linux ARM system that is showing significantly less throughput than expected on both Ethernet and USB. I suspect the memory may be contributing. Is there a way to observe the memory ...
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How to limit application memory usage?

I have spend 2 hours reading questions about this matter, and still there is some misunderstanding. I have this process: USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1452 0.4 1.8 ...
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What does the vm.swappiness parameter really control?

Per the kernel documentation: This control is used to define how aggressive the kernel will swap memory pages. Higher values will increase aggressiveness, lower values decrease the amount of swap. ...
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1answer
648 views

What is the optimum swap size on Linux for a heavily threaded program?

I using an Amazon EC2 server small instance and by default it allows 382 threads per process. However, I wish to run 10,000 threads in a single process. Recently, I learned that this can be done by ...
2
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0answers
311 views

Odd Inode/Ram cache drops happening in CentOS

I run a CentOS 5.7 machine (64bit) with 24GB ram and 4x SAS drives in RAID10 setup. This machine runs nginx/1.0.10, php-fpm & xcache. About a month back the RAM usage of this machine has changed. ...
7
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getrusage system call: what is “maximum resident set size”

man getrusage 2 says ru_maxrss (since Linux 2.6.32) This is the maximum resident set size used (in kilobytes). For RUSAGE_CHILDREN, this is the resident set size of the largest ...
2
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1answer
98 views

application to see the cpu architecture in a figure

I remember there was an application that showed, in the console, or in a simple picture, the memory architecture of the system: what caches were shared by which processors, etc. but I can't remember ...
2
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0answers
144 views

Need good ideas about improving any Linux service [closed]

I have a project assigned to me by OS teacher to choose any Linux service and improve it. Currently I am totally blank in this. I am not sure which service should I use which can easily be implemented ...
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3answers
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What is the formula to determine how much memory a socket consumes under Linux?

I'm doing some capacity planning and I was wondering if there is a formula that I could use to predict (from a memory standpoint) how many TCP connections I could handle on my server. At the moment, ...
6
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1answer
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Why does Linux show both more and less memory than I physically have installed?

I know about swap - this question isn't about that. In dmesg, the Linux (x86-64) kernel tells me this about how much memory I have: [ 0.000000] Memory: 3890880k/4915200k available (6073k kernel ...
3
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1answer
402 views

Impossible pmap results

Nautilus is taking up 450 MiB according to System Monitor (Ubuntu 10.04). $pmap <PID of Nautilus> ... total 1578276K Is pmap reporting 1.5 GiB of memory here? I'm trying to find out ...
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3answers
548 views

Is there a way to tell the system to keep a folder to reside in memory?

I'm developing a Java EE web application and I'm trying to speed up the testing process. To do so I was wondering if there is a way to tell the system to keep my build folder in system memory?
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How to limit available virtual memory per process

Occasionally some processes on my GNU/Linux desktop (such as gv and gnash) use up the physical memory and cause thrashing. Since these processes aren't important, I want them to be automatically ...
8
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1answer
2k views

System hanging when it runs out of memory

I've got an eeePC 900a: it has a 8GB flash as disk and only 1GB of RAM. The Linux distribution installed on it is ArchLinux. When the system runs out of memory it becomes extremely unresponsive: it ...
2
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2answers
283 views

Memory reporting issues

When I view the system monitor it reports that I'm only using 48% of ram. Same with gkrellm. But all of the command line utilities report different. Here is the output to free and /proc/meminfo. ...
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3answers
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How to get free memory on AIX?

How can I see the free memory on an AIX? There is no free -m under it. AIX oslevel: 6100-03-03-0943
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2answers
397 views

What tool(s) should I use to test my hardware for errors?

Are there any Linux tools (command line, or Live CD) that will test hardware components for errors (hard drive, RAM, CPU, graphics card, buses) and show me some detailed output with wrong parts etc.?
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2answers
702 views

Restricting memory area for linux kernel

I am running ltib Linux on P1022RDK (P1022 Core) platform. I have 512 MB = 0x20000000 memory. I want my Linux kernel to use the second half of the board memory (i.e from 256 MB to 512 MB) and want the ...
2
votes
2answers
776 views

Xvfb does not release memory

We want to create screenshots of websites for our software, and we are doing this by using CutyCapt with Xvfb. Unfortunatly every time CutyCapt takes a screenshot, the memory of Xvfb increases .. ...
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3answers
114 views

What is the lowest level I can see my system running?

Let me try and clarify. Is there any way for me to see very very low level activity on my computer? Stuff like: register content opcodes being sent specific memory addresses Or anything lower ...
2
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2answers
427 views

Measuring CPU and Memory per user to distribute “cost” of a server

How should I implement approximately correct per-user monitoring on a server? I want a way to split the cost of a server between the users based on their usage. On newer machines (RHEL6) I would use ...
8
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4answers
2k views

Suspend/resume single process to/from disk

On occasion, we would like to suspend memory-intensive processes on our Ubuntu and OS X servers to temporarily free up some RAM for other jobs. If all we were worried about was CPU usage, a simple ...
3
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1answer
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How to find out total memory resource usage with ps?

With ps command I can find out how much memory each program uses: ps -u mertnuhoglu -o pcpu,rss,pid,command Is it possible to find out the sums of each type of resource usage as well, easily?
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Increasing kernel memory size

I have an embedded board with 512MB of RAM running Linux 2.6.29 and UBoot bootloader. But the kernel is able to utilize only 128MB of RAM. I tried changing the value of XCODE_MEMSIZE, which I think ...
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1answer
526 views

How can I search/browse in some process's memory?

I'm using MacOS X 10.7 and I'm not very familiar with unix. Is there a command for a search in some process's memory for a string?
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1answer
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Is the file table in the filesystem or in memory?

In the context of operating system control tables, does the term "file tables" refer to a data structure that is part of the filesystem, or that is in main memory (and in which case I assume it would ...
4
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1answer
697 views

Behavior of mmap'd memory on memory pressure

I have a large tar file (60GB) containing image files. I'm using mmap() on this entire file to read in these images, which are accessed randomly. I'm using mmap() for the following reasons: Thread ...
3
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2answers
271 views

Access memory via a flat file in Linux

I understand everything is a flat file in Linux. How hard is it to dump the contents of the main memory into a flat file? Does it already exist in Linux? If yes, what's the path to the file? What are ...
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2answers
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gnome-keyring-daemon couldn't allocate secure memory

I run logcheck on my Debian Linux system to get alerted to unusual lines in my log files, and recently I saw the following in /var/log/messages: gnome-keyring-daemon: couldn't allocate secure memory ...
2
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1answer
111 views

Is there any method to mount a block of memory as a filesystem in linux?

I have a question,in linux, is there any method to mount a block of memory as a filesystem? For example, in X86 architecture, when power on, I reserve a block of memory about 8 Mbytes, and then when ...
6
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2answers
925 views

Difference between free -m and ps -euf

I'm not an expert on linux so I do apologize in advance for the silly question. I have a vps machine with ubuntu 10.04 and 512Mb of RAM. I'm trying to guess how much memory is available after running ...
12
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1answer
505 views

Does window minimizing free memory usage?

Both the undisplayed maximized window and minimized window are invisible to the end user. By undisplayed I mean an inactive maximized window covered by the active window. There is a difference ...
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Measuring RAM usage of a program

time is a brilliant command if you want to figure out how much CPU time a given command takes. I am looking for something similar that can measure the max RAM usage of the program and any children. ...
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1answer
474 views

Is there a way to kick kswapd and make it swap out pages?

Even though I have set swappiness to 100 and enabled swap, nothing is being swapped out. This is probably because I don't have high memory pressure at the moment. For testing purposes though, I want ...
7
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3answers
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Linux Kernel logical address space organisation

According to "Write Great Code" in almost all OS run time memory is organized into following regions: OS | Stack | Heap | Text | Static | Storage/BSS [In increasing address fashion] User ...
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vote
1answer
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Disable Address space layout randomization (ASLR) for my processes

I want to run some programs in Linux where I want to disable Address Space Layout Randomization (ASLR). I know to disable it at system level, which is by setting /proc/sys/kernel/randomize_va_space to ...
10
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2answers
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Why does my system show only 3.2 GiB of RAM when I definitely have 4.0 GiB

I have 2x2 GiB sticks of RAM installed. Running memtest86 from the grub boot menu confirms this.. memtest86 reports no errors. However every which way I check my available memory in a running ...
1
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1answer
293 views

What are the Implications of moving to Huge mem kernel on RHEL4

I've been asked to investigate adding extra memory (> 16gb) to a RHEL 4 server and moving to a huge mem kernel. The server is used for Oracle RAC. Is it just a case of installing the hugh mem kernel ...
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2answers
2k views

How to check for hardware errors with software methods?

How can I check for bad blocks, bad memory, etc. using only software solutions? I'm using Ubuntu 11.04.
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840 views

Limiting the Size of Apache HTTPD Memory Footprint

I have a web server running Cent OS 5 with Apache. I have over 1GB of Ram and the MaxSpareServers set to 15. This would be fine under most situations, but for some reason my httpd processes are ...
22
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4answers
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How to limit resource usage to save CPU+RAM for a certain process?

I have a dev server on which sshd sometimes stops working because the machine runs out of RAM. Yes we are running low on memory and upgrading is not a feasible choice right now. What I want to do is ...
10
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2answers
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real memory usage

if I understand correctly, in the following output produced by free, 3535m is the actual free memory available to applications, only 413m is used, is this correct? need some clarification on the ...
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1answer
375 views

Fedora 15 - Limited RAM Access

I have an issue with Fedora 15's available memory. The laptop it is installed on has 4GB of SDRAM, but Fedora only sees 2GB. [njozwiak@calvin xpmc6720]$ free -m total used ...
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0answers
553 views

How to find memory per core on multicore CPU?

This is required information for some MPI using app that I am working with... From its Makefile template: #insert memory per core and uncomment the following line #PREPROC= -D'MB_PER_CORE=750' ...
5
votes
4answers
979 views

Does optimizing for size reduce runtime memory usage as well as binary size?

Does optimizing for size with gcc -Os only reduce the binary size of a program, or does it reduce its runtime memory usage as well? I know what exactly the results are depend on the specific code, but ...
3
votes
1answer
660 views

Solution to get data from memory of a process

If I'm using Firefox and filling out a big form (with lots of text to write), and for some reason I accidentally press F5 and all my text in the forms is lost, I can use e.g. HxD on Windows to ...
3
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328 views

VMO Changes After Adding New RAM To AIX?

We have a server at a client site running AIX 5.3, which we just up the RAM to 32GB, from initially 16GB (if I'm not mistaken). This server is our Application server running J2EE applications on top ...
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635 views

Linux kernel slab usage growing on embedded system

I'm in the process of QA/debugging a project on a custom embedded linux system. The problem we're VERY tight on memory, and even a couple megs can cause issues with our software. What I'm seeing ...
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471 views

Unpredictable memory explosions

The main server at my company has recently been having a lot of downtime. For reasons that neither I nor the other admins can determine, it has random (VERY sudden) explosions in memory. It becomes ...
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1answer
872 views

CentOS 5.6 x86 64 Not seeing all my memory

So I installed CentOS 5.6 on a box at my house and it is not recognizing all my memory. I have 2gb in the machine but when you run a 'free -m' or a 'top' or a 'cat /proc/meminfo' it only shows that ...