The sysctl is a Unix interface used to modify variables that the kernel uses to determine behavior. There are two ways to work with sysctl: by directly reading and modifying files in /proc/sys and by using the sysctl program supplied with most distributions. The regedit interface is the closest parallel for Windows.
Questions tagged [sysctl]
174 questions
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vote
1 answer
OS X getting remote process input args sometimes fails
i would like to retrieve remote process input arguments programmatically,
so i used sysctl in the following manner (partial code) :
int mib[3]
mib = {CTL_KERN, KERN_ARGMAX,0,0}
size = sizeof(argmax);
if (sysctl(mib, 2, &argmax, &size, NULL, 0)…
Zohar81
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1
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1 answer
Performance tuning via sysctl, what is the difference between setting net.core.rmem_default (r/w) / net.ipv4.tcp_mem / net.ipv4.udp_mem
What is the difference between setting read/write mem default via net/core and setting the protocol min/max/default net/ipv4 in sysctl?
Detailed explanation or resource request
net.core.wmem_default
net.core.rmem_default
net.ipv4.tcp_mem
…
jc_
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1
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3 answers
How to avoid Undertow Connection RESET in apache benchmark test?
Using apache benchmarking 100K request 20K concurrent users:
$ ab -n 100000 -c 20000 http://localhost:8080/mrs/ping
Completed 10000 requests
Completed 20000 requests
Completed 30000 requests
Completed 40000 requests
Completed…
Matthew Ong
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1
vote
2 answers
Linux Command to set TCP window size
I want to send TCP packet with window size 65535 (0xffff). I m looking to set the TCP window size to 65535 on my linux system.
I know that there is the sysctl command but I could not find how tochange the tcp window.
How I can do that on my linux…
MOHAMED
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1
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4 answers
Enable Packet Forwarding
I am using Fedora 20 after running this command:
"sysctl -w net.inet.ip.forwarding=1"
it is giving this error:
"sysctl: cannot stat /proc/sys/net/inet/ip/forwarding: No such file or
directory"
techboyz
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1
vote
0 answers
Why sysctl disables ipv6 for new created interface?
I'm creating interface with IPv6 address using this answer:
https://stackoverflow.com/a/8338398/2317204
On ubuntu (x86_64) everything works fine, however on angstrom linux I see the failure of ioctl setting SIOCSIFADDR flag. So, I can create…
shahan
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1
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1 answer
array of CPUSTATES uint64_ts (user, nice, sys, intr, idle) in ubuntu
I required a command in ubuntu to get cpustats, like array of CPUSTATES uint64_ts(user, nice, sys, intr, idle), in FreeBSD when i give command
"sysctl -a | grep kern.cp_time"
I am able to get the information in FREEBSD command given above.. what…
vaibhav beohar
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1
vote
1 answer
Docker 0.9 - /etc/sysctl.conf not working
I set net.core.somaxconn = 65535 in /etc/sysctl.conf inside an Ubuntu image.
But the net.core.somaxconn turns to 128 in the container using command sysctl -a | grep net.core.somaxconn.
After I execute sysctl -p, it turns to 65535.
Why doesn't…
Tallmad
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1
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1 answer
errno: 38 (Function not implemented) on a call to change sysctl value
I want to set some local sysctl parameters with my program and I followed the directions given here: http://www.linux.it/~rubini/docs/sysctl/
As an example, here's what I'm doing to set the value for /proc/sys/net/ipv6/conf/tun0/accept_ra. I just…
SuPra
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1
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2 answers
How to find the value of kernel.shmmax from C code
I want to get the value of kernel.shmmax in C code (which I query on centos5.0, centos6.0 and ubuntu10.04 using the shell command "$ sysctl -q kernel.shmmax").
I used the following code to find it:
#include
const int…
mukul
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1
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1 answer
Check what device are You running and execute action
I've written this script:
#!/bin/sh
DEVICE=`sysctl hw.machine`
if [ $DEVICE = "hw.machine: iPhone3,1" ]
then
echo "Test Done"
else
echo "Test failed"
fi
After I run it I've got a message: ./test: line 5: [: too many arguments why isn't it…
Andrzej Florek
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1
vote
2 answers
freebsd shpgperproc what is responsible for?
i've googled a lot about what is "page share factor per proc" responsible for and found nothing. It's just interesting for me, i have no current problem with it for now, just curious (wnat to know more). In sysctl it is:
vm.pmap.shpgperproc
Thanks…
milo
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0 answers
sysctl hook in ios 15 leads to no mobile network connection
Hi i am hooking sysctl on ios 15, i have problem after hooking, imei code disappears, sim and mobile network service lose connection, can anyone help me!
Here is code Objective C++ and Logos:
int (* original_sysctl)(const int *name, u_int namelen,…
dinhthiet
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votes
0 answers
Modifying tcp_options and tcp_options_seq
I was trying to modify tcp options parameters using sysctl, but nothing seems to work.
for example:
mac machine has following tcp_options seq:
mss,nop,ws,nop,nop,ts,sok,eol,eol
windows has:
mss,nop,ws,nop,nop,sok
linux has:
mss,sok,ts,nop,ws
how can…
shashank mohabia
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0
votes
0 answers
Martian source and sysctl
Okay, so I have one machine with this config:
net.ipv4.conf.all.log_martians = 0
net.ipv4.conf.default.log_martians = 0
And, after a sysctl -p, it stopped flooding the /var/log/messages (as it should).
But I have this other machine, with an sdiff…
Alan Mackey
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