procfs (or the proc filesystem) is a special filesystem in UNIX-like operating systems that presents information about processes and other system information in a hierarchical file-like structure

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Accounting for /proc/net/dev reported traffic

I noticed that according to /proc/net/dev I am constantly receiving around 6Kb/s on my wireless usb interface. But I can't account for anything even close to that with the individual connections that ...
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/proc/net/wireless does not show values unless run as root

cat /proc/net/wireless does not show statistics for wireless devices unless it is run as root, even though the permissions on the file are 444. The same seems to apply when accessing statistics via ...
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Programmatically get CPUs 'detailed' usage, like top/htop

htop has a great way to show CPU usage. It shows the activity (usage in %) of each cores, and each core gauge is divided into three parts : blue: low priority processes green: normal processes red: ...
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Why is the size of “/proc/kcore” file so bigger than the physical memory size?

From proc manual: /proc/kcore This file represents the physical memory of the system and is stored in the ELF core file format. With this pseudo-file, and an unstripped kernel (/usr/src/...
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How is /proc/net files getting populated in Linux/Unix?

I'm working on a network monitor for Linux, without packet sniffing. I'm planning to read the network statistics and related data from /proc/net files. I know that /proc is the mount point of process ...
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Determine how much a process is using each disk?

How do I tell how much load a particular process is contributing to each of several available volumes/mounts? It seems that dstat only shows aggregate stats across all processes per disk, and iotop ...
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Linux Performance Measurements using /proc/vmstat

Am new to Linux, Please any one help. I want to calculate Input output performance using /proc/vmstat file? when i run command cat /proc/vmstat | grep pgpg The answer is pgpgin 726854 pgpgout ...
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Very large values for utime and stime for foo. Is foo still running?

I am running a program foo It has been running for close to 30 days now (even more) Until around 10 days ago (I cannot be very exact) it used 100% of one cpu on my dual core laptop (it was at the ...
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Strange cpu usage values reported by pidstat

I have a script that reports the cpu usage of a specific program reading values from pidstat. The script launches as: pidstat -C ^frontend$ -h -l -p ALL 1 1 The values reported this way sometimes ...
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Is there a way to show all flags in /proc/mounts?

Some filesystem flags seem to be hidden in /proc/mounts, depending on whether they are defined as defaults. Is there a way to show all flags in /proc/mounts, also including the default ones? And if ...
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Owner can't read /proc/$pid/io

On CentOS 7, I am trying to debug an issue where the nginx amplify agent cannot read /proc/$pid/io even though it is owned by the proper user. One of the nginx worker processes right now is pid 5693: ...
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Significance of Linux kernel's default_console_loglevel

What is the significance of default_console_loglevel in Linux? Commonly I see it described as the default value of console_loglevel. However, what that means I haven't seen explained anywhere. ...
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Why does each process folder under /proc contain the same information?

Under /proc/<PID>/net pseudo-file system each process seems to have files with the same content. For example I use cat /proc/<PID>/net/ip_tables_names to list iptables tables under the ...
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OOM Killer: Processes have a score of over a 1000

All top links when Googling for OOM score seem to indicate that the values must be between -1000 and 1000. I tried to verify that with a simple cat /proc/*/oom_score | sort -n | less and I ...
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279 views

Portable way to parse /proc/meminfo

I'm having trouble finding a generic code that work, here, for both CentOS 5/6 and CentOS 7 versions pc the /proc/meminfo file. I Want to compute the "Real Used memory" like free does. (amounts ...
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Disk I/O latency using /proc/vmstat file

How do I calculate disk read and write latency in Linux? Is it possible to do the calculation using /proc file system? I am using iostat and vmstat command. But I do not understand how the ...
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372 views

Monitor the creation of new processes

I want to get a notification whenever a new process is created. I've tried to use inotify on /proc, but it didn't report any event even though a new directory appeared in /proc. I could list the /...
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What are the /proc/drivers directories organisation for nouveau or radeon

The context: I need to get some basic informations from the graphic card in a lib in lua. The idea is to not rely on external software (like hwinfo for example). I know that for a system with an ...
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sar command vs /proc/stat for cpu usage

I have been using /proc/stat for calculating the cpu usage. Recently I have been going through sar command for calculating cpu usage. And what I found was that their values were not related (I was ...
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There is no /proc/bus/usb directory

I'm running a centos VM on ESXi. Does the /proc/bus/usb directory not show up until a USB device is connected? I just added a USB controller to the VM (it previously had non) and ran lsusb: $ ...
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proc system interrupts information

There are many info under /proc For examples, for each process : raw format : cat /proc/< pid >/stat human readable : cat /proc/< pid >/status My goal is to read the info ...
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code generating /proc file system

In my assignment, I have added "casper" flag to task descriptor and it takes only 0, 1, 2 and 3 (default 0). I asked to "modify the code that generates the /proc filesystem so that its behavior is ...
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What does the “ss -s” result “Total:” value represent? How to get details on each of them?

I am trying to understand what the ss -s result line Total: value represents, along with how this number is related to the other numbers. Note, the following values are equivalent: ss -s Total: == ...
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What is kswapd_low_wmark_hit_quickly from /proc/vmstat

What does this parameter mean? # cat /proc/vmstat | grep low kswapd_low_wmark_hit_quickly 2
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How to know file name of sockets or pipes in /proc/[pid]/fd

In Android, #ls -l 15843/fd gives following output, lrwx------ u0_a179 u0_a179 2015-05-28 11:58 90 -> socket:[193728] lrwx------ u0_a179 u0_a179 2015-05-28 11:58 91 -> ...
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How can I get read/write instant speed of a Hard Drive using /proc/diskstats data?

I know that the proc/diskstats file presents these data columns: 1 - major number 2 - minor mumber 3 - device name 4 - reads completed successfully 5 - reads merged 6 - sectors read 7 - time spent ...
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/proc/stat - is guest counted into user time?

I have a quick question. In man page for /proc/stat this is not clear to me: Is guest and guest_nice time included in user time in /proc/stat? http://man7.org/linux/man-pages/man5/proc.5.html in ...
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Value of /proc/sys/kernel/hostname

I've set computer hostname in /etc/hostname a while ago (also there are record in /etc/hosts). Everything worked fine, but recently I've noticed that value of hostname (and /proc/sys/kernel/hostname) ...
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Viewing shared segments created by shmget

I'm trying to "visualize" shared memory between two processes. I've created a little server-client example where the client writes some data to a shared memory location and the server reads from it. I'...
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402 views

Process VSS and Size: entry in /proc/pid/smaps

I was wondering why the sum of all 'Size:' entries in /proc/pid/smaps does not equal the process VSS as reported by top, ps, /proc/pid/status VmSize, /proc/pid/statm 1st entry? Any clues?
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Rogue Java process brings my computer to a halt

In reference to my earlier post: Is there a log of past threads that are now closed? I gave the process a kill -STOP signal and started examining the details. I can't seem to figure out why it is ...
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What's the meaning of the letter 's' in file name “/proc/$$/smaps”?

I know /proc/$$/maps means sections in a process' virtual address space. However, I cannot guess the meaning of the letter s in file name /proc/$$/smaps. Any explanations?
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Strange PFN read from pagemap

I m trying to find the physical page to which a range of virtual addresses are mapped in a piece of C code that I ve written. I m using the /proc/self/pagemap to read the mapping. I ve used the code ...
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How to get the path of a current running script file?

Knowing that program's PID, I want to list out the executable file of a running program. For binary programs, I can read /proc/$pid/exe, which is a symlink to the executable. However for scripting ...
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This name appears in multiple /proc/interrupts

The name of the interrupt appears as follows: Multiple.. (85:exynos4210-uart) root@test:~# cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 28: 3543629726 1086578047 3268216812 ...
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fsync () get the impact of road /proc/sys/vm/drop_caches?

I have been testing the service life of TLC(1000write) SD card (4GB). SD card has been formatted with a fat partition. I am a write (), fsync () on a file of 10M SD card repeatedly. 1st (10M): ...
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Why number of dirty pages is always 0 on 2.6?

In /usr/src/linux/Documentation/filesystems/proc.txt i've found the string: Table 1-3: Contents of the statm files (as of 2.6.8-rc3) .....................................................................
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How to change the console_loglevel in linux?

I read at multiple places (e.g. here http://elinux.org/Debugging_by_printing), that you can change the console log level by echoing an integer to /proc/sys/kernel/printk. If that worked shouldn't the ...