I have nodejs application (as a server) deployed as a Docker container and I want to count the number of executed instructions when I call a function in it.
Here is how I find the container's PID:
$ pstree -p | grep node | grep npm
| |-containerd-shim(114397)-+-npm(114414)-+-sh(114540)---node(114541)-+-{node}(114542)
Then, I need to know the Docker ID:
$ docker ps | grep workload
root#node3:/home/m# docker ps | grep workload | grep npm
c7457f74536b michelgokan/synthetic-workload-generator "npm start" 55 minutes ago Up 55 minutes k8s_whatever_workload-5697bb48f9-gg8j5_default_896e5938-55f2-4875-bf6c-2bff2acbe0c6_0
Now, I know the parent PID is 114397. So I run the following perf command:
$ perf stat -p 114397 -e instructions,cycles,task-clock docker exec -it c7457f74536b curl 127.0.0.1:30005/workload/cpu
1000 CHKSM AND DIFFIEHELLMAN 60 OK!
Performance counter stats for process id '114397':
170057460 instructions # 1.02 insn per cycle
166389574 cycles # 1.575 GHz
105.67 msec task-clock # 0.570 CPUs utilized
0.185362408 seconds time elapsed
It seems it's not including instructions executed by the child processes. So I tried the following:
$ perf stat -p 1,722,114397,114414,114540,114541,114542 -e instructions,cycles,task-clock docker exec -it c7457f74536b curl 127.0.0.1:30005/workload/cpu
1000 CHKSM AND DIFFIEHELLMAN 60 OK!
Performance counter stats for process id '1,722,114397,114414,114540,114541,114542':
249803992 instructions # 1.05 insn per cycle
236979702 cycles # 1.575 GHz
150.47 msec task-clock # 0.832 CPUs utilized
0.180848729 seconds time elapsed
In which 1 is the systemd and 722 is the parent containerd PID of
containers.
Questions:
Is there any way that I can provide the parent PID and it counts number of executed instructions of all processes?
Does my approach make sense? I mean the way I provided all the PIDs in a comma-separated format.
You can get the PID of one of you processes (the parent) and deduce the others using pgrep.
pgrep has a neat feature --ns which will get you all the processes running in the same PID namespace as a given PID.
Having that you can get all the child process and convert them to comma separated values and feed them to perf
$ perf stat -p $(pgrep --ns <pid> | paste -s -d ",") -e instructions,cycles,task-clock docker exec -it c7457f74536b curl 127.0.0.1:30005/workload/cpu
pgrep --ns will get you the pid and paste -s -d "," will convert them.
I need something like $command & stop This should execute a command and suspend it. The application later resumes back the command for complete results.
I understand that job can be suspended with stop signal to the corresponding pid.
$kill -SIGSTOP 12753
When we execute a command, we barely know its pid. There is extra command involved to take a pid and do the required. I want to avoid the extra command and a time interval.
Basically The application is for a measure of network performance. Trigger all the commands put them in halt mode. The halted commands are resumed back as per the kind of traffic needed.
The process ID of the most recently started background command is available in the shell parameter $!:
$ command & kill -SIGSTOP $!
(Check the documentation for your shell's implementation of kill for the correct format.)
Try killall with the --signal option where you can specify the name of the process.
linux:~ # killall
Usage: killall [OPTION]... [--] NAME...
killall -l, --list
killall -V, --version
-e,--exact require exact match for very long names
-I,--ignore-case case insensitive process name match
-g,--process-group kill process group instead of process
-i,--interactive ask for confirmation before killing
-l,--list list all known signal names
-q,--quiet don't print complaints
-r,--regexp interpret NAME as an extended regular expression
-s,--signal SIGNAL send this signal instead of SIGTERM
-u,--user USER kill only process(es) running as USER
-v,--verbose report if the signal was successfully sent
-V,--version display version information
-w,--wait wait for processes to die
Verified by starting md5sum in a shell session:
linux$ md5sum
and in another session, ran:
killall -s SIGSTOP md5sum
yielding the following in the md5sum session:
[1]+ Stopped md5sum
Kindly confirm if you want to halt your command or run in background(append '&' to your command)?
If your application is expected to start halted command later, then why dont you start your command(to be halted) in that application itself.
This helps :
sleep 5 & kill -SIGSTOP $!
In above, have executed sleep(demo command) for 5 seconds in background.
Next have send to kill for stopping it using its PID obtained by $!.
Demo & kludge using timeout, (for some reason timeout intereprets a '0s' duration as "run forever"), to stop yes before it outputs anything:
# run 'yes' command, let it print 5 numbered lines, but stop it immediately
timeout -s SIGSTOP .000000001s yes | head -n 5 | cat -n
Output (to STDERR):
[1]+ Stopped timeout -s SIGSTOP .000000001s yes | head -n 5 | cat -n
Now restart it:
fg > /dev/null
Output:
1 y
2 y
3 y
4 y
5 y
Technique for users stuck with v8.12 or earlier coreutils, (pre-2011), wherein timeout lacks sub-second intervals. Requires waiting a second.
Wrap the command string in a shell invocation, preceded by a 1s wait -- so timeout waits 1 second, and simultaneously, so does the command string. Total wait time 1 second:
timeout -s SIGSTOP 1s sh -c "sleep 1s; yes | head -n 5 | cat -n"
Output is the same as before, fg is the same too.
Finesse, if waiting even 1 second before sleeping is too much, it can be run in the background like so:
timeout -s SIGSTOP 1s sh -c "sleep 1s; yes | head -n 5 | cat -n" &
Output (process number will vary):
[1] 14601
Then after a second, the output will be the same as the previous two timeout examples.
Assuming you are using the same command, find the command name in ps output, you can launch it in one terminal then open a new terminal
ps -ely
after retrieving the command name:
command & kill -SIGSTOP $(pidof command_name)
pidof needs the exact command name to be able to find the pid.
then to resume it:
kill -SIGCONT $(pidof command_name)
if the command name is not constant, but there is a pattern, you can create a script like this, you can call it pof.sh:
ps -ely | grep $1 | tr -s ' ' | cut -d" " -f3
command & kill -SIGSTOP $(bash pof.sh pattern)
One drawback with this script, is that in case many lines match the pattern it will returns all of theirs pids, if this is a problem, you can put the output in an array and go on from there.
I would like to keep a process running for a long time (e.g., more than half an hour). My program is gpg. If I encrypt a 500MB file using gpg elgamal encryption, it takes around 1-2 minutes (compression is turned off). To increase the running time, I can only create a file with a few GB, which is not desirable. Is there any other way to make this gpg program run for longer time?
I believe, by default, gpg takes its input from standard input and sends output to standard output.
So you could make it run forever with something like:
gpg --encrypt </dev/urandom >/dev/null
To use that for consuming CPU for an hour (for example), you could create a script like:
gpg --encrypt </dev/urandom >/dev/null &
pid=$!
sleep 3600
kill -9 ${pid}
https://unix.stackexchange.com/questions/18869/slow-down-a-process-without-affecting-other-processes
CPULimit might do what you need without affecting other processes:
http://www.cyberciti.biz/faq/cpu-usage-limiter-for-linux/
You start the program, then run cpulimit against the program name or PID, specifying what percentage you want it limited. Note the percentage is of all cores; so if you have 4 cores, you could use 400%.
I want to limit the execution time of a program I am running under Linux. I put in my scons script a line like:
Command("com","","ulimit -t 1; myprogram")
and tested it with an infinite loop program: it did not work and the program ran forever.
Am I missing something?
-- tsf
ulimit -t 1 means that the limit is set to 1 second of CPU time. If your infinite loop program uses any sort of sleep in its inner loop then it will use practically no CPU time. This means it will not get killed in 1 second of real, on the clock time. In fact it may take minutes or hours to use up its 1 second allocation.
What happens if you run the command outside of SCons? Perhaps you don't have permission to change the limit at all...
ulimit -t 1; ./myprogram
For example, it may say the following if the limit is already set to 0:
bash: ulimit: cpu time: cannot modify limit: Operation not permitted
Edit: it seems that the -t option is broken on Ubuntu 9.04. A fix has been committed 05 June 2009, but it may take a while to trickle into the updates - it may not be fixed until 9.10.
As an historical note, this problem no longer exists in Ubuntu 10.04.
You can also use this script:
(taken from http://newsgroups.derkeiler.com/Archive/Comp/comp.sys.mac.system/2005-12/msg00247.html)
#!/bin/sh
# timeout script
#
usage()
{
echo "usage: timeout seconds command args ..."
exit 1
}
[[ $# -lt 2 ]] && usage
seconds=$1; shift
timeout()
{
sleep $seconds
kill -9 $pid >/dev/null 2>/dev/null
}
eval "$#" &
pid=$!
timeout &
wait $pid
.
I have the following problem: some processes, generated dynamically, have a tendency to eat 100% of CPU. I would like to limit all the process matching some criterion (e.g. process name) to a certain amount of CPU percentage.
The specific problem I'm trying to solve is harnessing folding#home worker processes. The best solution I could think of is a perl script that's executed periodically and uses the cpulimit utility to limit the processes (if you're interested in more details, check this blog post). It works, but it's a hack :/
Any ideas? I would like to leave the handling of processes to the OS :)
Thanks again for the suggestions, but we're still missing the point :)
The "slowDown" solution is essentially what the "cpulimit" utility does. I still have to take care about what processes to slow down, kill the "slowDown" process once the worker process is finished and start new ones for new worker processes. It's precisely what I did with the Perl script and a cron job.
The main problem is that I don't know beforehand what processes to limit. They are generated dynamically.
Maybe there's a way to limit all the processes of one user to a certain amount of CPU percentage? I already set up a user for executing the folding#home jobs, hoping that i could limit him with the /etc/security/limits.conf file. But the nearest I could get there is the total CPU time per user...
It would be cool if to have something that enables you to say:
"The sum of all CPU % usage of this user's processes cannot exceed 50%". And then let the processes fight for that 50% of CPU regarding to their priorities...
Guys, thanks for your suggestions, but it's not about priorities - I want to limit the CPU % even when there's plenty of CPU time available. The processes are already low priority, so they don't cause any performance issues.
I would just like to prevent the CPU from running on 100% for extended periods...
I had a slightly similar issue with gzip.
Assuming we want to decrease the CPU of a gzip process:
gzip backup.tar & sleep 2 & cpulimit --limit 10 -e gzip -z
Options:
I found sleep useful as the cpulimit sometimes didn't pick up the new gzip process immediately
--limit 10 limits gzip CPU usage to 10%
-z automatically closes cpulimit when gzip process finishes
Another option is to run the cpulimit daemon.
I don't remember and dont think there was something like this in the unix scheduler. You need a little program which controls the other process and does the following:
loop
wait for some time tR
send SIGSTOP to the process you want to be scheduled
wait for some time tP
send SIGCONT to the process.
loopEnd
the ratio tR/tP controls the cpu load.
Here is a little proof of concept. "busy" is the program which uses up your cpu time and which you want to be slowed-down by "slowDown":
> cat > busy.c:
main() { while (1) {}; }
> cc -o busy busy.c
> busy &
> top
Tasks: 192 total, 3 running, 189 sleeping, 0 stopped, 0 zombie
Cpu(s): 76.9% us, 6.6% sy, 0.0% ni, 11.9% id, 4.5% wa, 0.0% hi, 0.0% si
Mem: 6139696k total, 6114488k used, 25208k free, 115760k buffers
Swap: 9765368k total, 1606096k used, 8159272k free, 2620712k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
26539 cg 25 0 2416 292 220 R 90.0 0.0 3:25.79 busy
...
> cat > slowDown
while true; do
kill -s SIGSTOP $1
sleep 0.1
kill -s SIGCONT $1
sleep 0.1
done
> chmod +x slowDown
> slowDown 26539 &
> top
Tasks: 200 total, 4 running, 192 sleeping, 4 stopped, 0 zombie
Cpu(s): 48.5% us, 19.4% sy, 0.0% ni, 20.2% id, 9.8% wa, 0.2% hi, 2.0% si
Mem: 6139696k total, 6115376k used, 24320k free, 96676k buffers
Swap: 9765368k total, 1606096k used, 8159272k free, 2639796k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
26539 cg 16 0 2416 292 220 T 49.7 0.0 6:00.98 busy
...
ok, that script needs some more work (for example, to care for being INTR-upted and let the controlled process continue in case it was stopped at that moment), but you get the point. I would also write that little script in C or similar and compute the cpu ratio from a comand line argument....
regards
I think in Linux there is no solution to cap the cpu usage, but there is an acceptable way to limit any process to a certain CPU usage: http://ubuntuforums.org/showthread.php?t=992706
In case they remove the info, here is again
INSTALL PACKAGES
Install cpulimit package.
Code:
sudo apt-get install cpulimit
Install gawk package.
Code:
sudo apt-get install gawk
CREATE CPULIMIT DAEMON FILE
Open text editor with root privileges and save bellow daemon script text to new file /usr/bin/cpulimit_daemon.sh
Code:
#!/bin/bash
# ==============================================================
# CPU limit daemon - set PID's max. percentage CPU consumptions
# ==============================================================
# Variables
CPU_LIMIT=20 # Maximum percentage CPU consumption by each PID
DAEMON_INTERVAL=3 # Daemon check interval in seconds
BLACK_PROCESSES_LIST= # Limit only processes defined in this variable. If variable is empty (default) all violating processes are limited.
WHITE_PROCESSES_LIST= # Limit all processes except processes defined in this variable. If variable is empty (default) all violating processes are limited.
# Check if one of the variables BLACK_PROCESSES_LIST or WHITE_PROCESSES_LIST is defined.
if [[ -n "$BLACK_PROCESSES_LIST" && -n "$WHITE_PROCESSES_LIST" ]] ; then # If both variables are defined then error is produced.
echo "At least one or both of the variables BLACK_PROCESSES_LIST or WHITE_PROCESSES_LIST must be empty."
exit 1
elif [[ -n "$BLACK_PROCESSES_LIST" ]] ; then # If this variable is non-empty then set NEW_PIDS_COMMAND variable to bellow command
NEW_PIDS_COMMAND="top -b -n1 -c | grep -E '$BLACK_PROCESSES_LIST' | gawk '\$9>CPU_LIMIT {print \$1}' CPU_LIMIT=$CPU_LIMIT"
elif [[ -n "$WHITE_PROCESSES_LIST" ]] ; then # If this variable is non-empty then set NEW_PIDS_COMMAND variable to bellow command
NEW_PIDS_COMMAND="top -b -n1 -c | gawk 'NR>6' | grep -E -v '$WHITE_PROCESSES_LIST' | gawk '\$9>CPU_LIMIT {print \$1}' CPU_LIMIT=$CPU_LIMIT"
else
NEW_PIDS_COMMAND="top -b -n1 -c | gawk 'NR>6 && \$9>CPU_LIMIT {print \$1}' CPU_LIMIT=$CPU_LIMIT"
fi
# Search and limit violating PIDs
while sleep $DAEMON_INTERVAL
do
NEW_PIDS=$(eval "$NEW_PIDS_COMMAND") # Violating PIDs
LIMITED_PIDS=$(ps -eo args | gawk '$1=="cpulimit" {print $3}') # Already limited PIDs
QUEUE_PIDS=$(comm -23 <(echo "$NEW_PIDS" | sort -u) <(echo "$LIMITED_PIDS" | sort -u) | grep -v '^$') # PIDs in queue
for i in $QUEUE_PIDS
do
cpulimit -p $i -l $CPU_LIMIT -z & # Limit new violating processes
done
done
CHANGE VARIABLES TO YOUR ENVIRONMENT NEEDS
CPU_LIMIT
Change this variable in above script if you would like to omit CPU consumption for every process to any other percentage then 20%. Please read "If using SMP computer" chapter bellow if you have SMP computer (more then 1 CPU or CPU with more then 1 core).
DAEMON_INTERVAL
Change this variable in above script if you would like to have more/less regular checking. Interval is in seconds and default is set to 3 seconds.
BLACK_PROCESS_LIST and WHITE_PROCESSES_LIST
Variable BLACK_PROCESSES_LIST limits only specified processes. If variable is empty (default) all violating processes are limited.
Variable WHITE_PROCESSES_LIST limits all processes except processes defined in this variable. If variable is empty (default) all violating processes are limited.
One or both of the variables BLACK_PROCESSES_LIST and WHITE_PROCESSES_LIST has to be empty - it is not logical that both variables are defined.
You can specify multiple processes in one of this two variables using delimiter characters "|" (without double quotes). Sample: if you would like to cpulimit all processes except mysql, firefox and gedit processes set variable: WHITE_PROCESSES_LIST="mysql|firefox|gedit"
PROCEDURE TO AUTOMATICALLY START DAEMON AT BOOT TIME
Set file permissions for root user:
Code:
sudo chmod 755 /usr/bin/cpulimit_daemon.sh
Open text editor with root privileges and save bellow script to new file /etc/init.d/cpulimit
Code:
#!/bin/sh
#
# Script to start CPU limit daemon
#
set -e
case "$1" in
start)
if [ $(ps -eo pid,args | gawk '$3=="/usr/bin/cpulimit_daemon.sh" {print $1}' | wc -l) -eq 0 ]; then
nohup /usr/bin/cpulimit_daemon.sh >/dev/null 2>&1 &
ps -eo pid,args | gawk '$3=="/usr/bin/cpulimit_daemon.sh" {print}' | wc -l | gawk '{ if ($1 == 1) print " * cpulimit daemon started successfully"; else print " * cpulimit daemon can not be started" }'
else
echo " * cpulimit daemon can't be started, because it is already running"
fi
;;
stop)
CPULIMIT_DAEMON=$(ps -eo pid,args | gawk '$3=="/usr/bin/cpulimit_daemon.sh" {print $1}' | wc -l)
CPULIMIT_INSTANCE=$(ps -eo pid,args | gawk '$2=="cpulimit" {print $1}' | wc -l)
CPULIMIT_ALL=$((CPULIMIT_DAEMON + CPULIMIT_INSTANCE))
if [ $CPULIMIT_ALL -gt 0 ]; then
if [ $CPULIMIT_DAEMON -gt 0 ]; then
ps -eo pid,args | gawk '$3=="/usr/bin/cpulimit_daemon.sh" {print $1}' | xargs kill -9 # kill cpulimit daemon
fi
if [ $CPULIMIT_INSTANCE -gt 0 ]; then
ps -eo pid,args | gawk '$2=="cpulimit" {print $1}' | xargs kill -9 # release cpulimited process to normal priority
fi
ps -eo pid,args | gawk '$3=="/usr/bin/cpulimit_daemon.sh" {print}' | wc -l | gawk '{ if ($1 == 1) print " * cpulimit daemon can not be stopped"; else print " * cpulimit daemon stopped successfully" }'
else
echo " * cpulimit daemon can't be stopped, because it is not running"
fi
;;
restart)
$0 stop
sleep 3
$0 start
;;
status)
ps -eo pid,args | gawk '$3=="/usr/bin/cpulimit_daemon.sh" {print}' | wc -l | gawk '{ if ($1 == 1) print " * cpulimit daemon is running"; else print " * cpulimit daemon is not running" }'
;;
esac
exit 0
Change file's owner to root:
Code:
sudo chown root:root /etc/init.d/cpulimit
Change permissions:
Code:
sudo chmod 755 /etc/init.d/cpulimit
Add script to boot-up procedure directories:
Code:
sudo update-rc.d cpulimit defaults
Reboot to check if script starts cpulimit daemon at boot time:
Code:
sudo reboot
MANUALLY CHECK, STOP, START AND RESTART DAEMON
Note: Daemon and service in this tutorial has equal meaning.
Note: For users using prior to Ubuntu 8.10 (like Ubuntu 8.04 LTS) instead of service command use "sudo /etc/init.d/cpulimit status/start/stop/restart" syntax or install sysvconfig package using command: sudo apt-get install sysvconfig
Check if cpulimit service is running
Check command returns: "cpulimit daemon is running" if service is running, or "cpulimit daemon is not running" if service is not running.
Code:
sudo service cpulimit status
Start cpulimit service
You can manually start cpulimit daemon which will start to omit CPU consumption.
Code:
sudo service cpulimit start
Stop cpulimit service
Stop command stops cpulimit daemon (so no new process will be limited) and also sets to all existing limited processes to have full access to CPU, just like it was before cpulimit was not running.
Code:
sudo service cpulimit stop
Restart cpulimit service
If you change some variables settings in /usr/bin/cpulimit_daemon.sh like CPU_LIMIT, DAEMON_INTERVAL, BLACK_PROCESSES_LIST or WHITE_PROCESSES_LIST, then after changing settings you must restart service.
Code:
sudo service cpulimit restart
CHECK CPU CONSUMPTION WITH OR WITHOUT CPULIMIT DAEMON
Without daemon
1. stop cpulimit daemon (sudo service cpulimit stop)
2. execute CPU intensive tasks in background
3. execute command: top and check for %CPU column
Result of %CPU is probably more then 20% for each process.
With daemon turned on
1. start cpulimit daemon (sudo service cpulimit start)
2. execute the same CPU intensive tasks in background
3. execute command: top and check for %CPU column
Result of %CPU should be maximum 20% for each process.
Note: Don't forget at beginning %CPU can be more then 20%, because daemon has to catch violating process in interval of 3 seconds (set in script by default)
IF USING SMP COMPUTER
I have tested this code on Intel dual-core CPU computer - that behaves like SMP computer. Don't forget that top command and also cpulimit by default behaves in Irix mode, where 20% means 20% of one CPU. If there are two CPUs (or dual-core) then total %CPU can be 200%. In top command Irix mode can be turned off with command I (pressing +i when top command is running) and Solaris mode is turned on, where total amount of CPU is divided by number of CPUs, so %CPU can be no more then 100% on any number of CPU computer. Please read more info about top command in top man page (search for I command). Please also read more about how cpulimit is operating on SMP computer in cpulimit official page.
But how does cpulimit daemon operates on SMP computer? Always in Irix mode. So if you would like to spend 20% of CPU power on 2-CPU computer then 40% should be used for CPU_LIMIT variable in cpulimit daemon script.
UNINSTALL CPULIMIT DAEMON AND CPULIMIT PROGRAM
If you would like to get rid of cpulimit daemon you can clean up your system by removing cpulimit daemon and uninstalling cpulimit program.
Stop cpulimit daemon
Code:
sudo service cpulimit stop # Stop cpulimit daemon and all cpulimited processes
Remove daemon from boot-up procedure
Code:
sudo update-rc.d -f cpulimit remove # Remove symbolic links
Delete boot-up procedure
Code:
sudo rm /etc/init.d/cpulimit # Delete cpulimit boot-up script
Delete cpulimit daemon
Code:
sudo rm /usr/bin/cpulimit_daemon.sh # Delete cpulimit daemon script
Uninstall cpulimit program
Code:
sudo apt-get remove cpulimit
Uninstall gawk program
If you don't need this program for any other script, you can remote it.
Code:
sudo apt-get remove gawk
NOTE ABOUT AUTHORS
I have just written daemon for cpulimit (bash scripts above). I am not the author of cpulimit project. If you need more info about cpulimit program, please read official cpulimit web page: http://cpulimit.sourceforge.net/.
Regards,
Abcuser
I had a similar problem, and the other solutions presented in the thread don't address it at all. My solution works for me right now, but it is suboptimal, particularly for the cases where the process is owned by root.
My workaround for now is to try very hard to make sure that I don't have any long-running processes owned by root (like have backup be done only as a user)
I just installed the hardware sensors applet for gnome, and set up alarms for high and low temperatures on the CPU, and then set up the following commands for each alarm:
low:
mv /tmp/hogs.txt /tmp/hogs.txt.$$ && cat /tmp/hogs.txt.$$ | xargs -n1 kill -CONT
high:
touch /tmp/hogs.txt && ps -eo pcpu,pid | sort -n -r | head -1 | gawk '{ print $2 }' >> /tmp/hogs.txt && xargs -n1 kill -STOP < /tmp/hogs.txt
The good news is that my computer no longer overheats and crashes. The downside is that terminal processes get disconnected from the terminal when they get stopped, and don't get reconnected when they get the CONT signal. The other thing is that if it was an interactive program that caused the overheating (like a certain web browser plugin!) then it will freeze in the middle of what I'm doing while it waits for the CPU to cool off. It would be nicer to have CPU scaling take care of this at a global level, but the problem is that I only have two selectable settings on my CPU and the slow setting isn't slow enough to prevent overheating.
Just to re-iterate here, this has nothing at all to do with process priority, re-nicing,and obviously nothing to do with stopping jobs that run for a long time. This has to do with preventing CPU utilization from staying at 100% for too long, because the hardware is unable to dissipate the heat quickly enough when running at full capacity (idle CPU generates less heat than a fully loaded CPU).
Some other obvious possibilities that might help are:
Lower the CPU speed overall in the BIOS
Replace the heatsink or re-apply the thermal gel to see if that helps
Clean the heatsink with some compressed air
Replace the CPU fan
[edit]
Note: no more overheating at 100% CPU when I disable variable fan speed in the bios (asus p5q pro turbo). With the CPU fully loaded, each core tops out at 49 celcius.
Using cgroups' cpu.shares does nothing that a nice value wouldn't do. It sounds like you want to actually throttle the processes, which can definitely be done.
You will need to use a script or two, and/or edit /etc/cgconfig.conf to define the parameters you want.
Specifically, you want to edit the values cpu.cfs_period_us and cpu.cfs_quota_us. The process will then be allowed to run for cpu.cfs_quota_us microseconds per cpu.cfs_period_us microseconds.
For example:
If cpu.cfs_period_us = 50000 and cpu.cfs_quota_us = 10000 then the process will receive 20% of the CPU time maximum, no matter what else is going on.
In this screenshot I have given the process 2% of CPU time:
As far as the process is concerned it is running at 100%.
Settings cpu.shares on the other hand can and will still use 100% of the idle CPU time.
In this similar example I have given the process cpu.shares = 100 (of 1024):
As you can see the process is still consuming all the idle CPU time.
References:
http://manpages.ubuntu.com/manpages/precise/man5/cgconfig.conf.5.html
http://kennystechtalk.blogspot.co.uk/2015/04/throttling-cpu-usage-with-linux-cgroups.html
In a system that uses systemd, you can run a single process with a maximum CPU usage using a command like the following:
sudo systemd-run --scope --uid=1000 -p CPUQuota=20% my_heavy_computation.sh
This will use up to 20% of a single CPU core (or CPU thread if using hyper-threading).
I also had the need to limit CPU time for certain processes. Cpulimit is a good tool, but I always had to manually find out the PID and manually start cpulimit, so I wanted something more convenient.
I came up with this bash script:
#!/bin/bash
function lp
{
ps aux | grep $1 | termsql "select COL1 from tbl" > /tmp/tmpfile
while read line
do
TEST=`ps aux | grep "cpulimit -p $line" | wc -l`
[[ $TEST -eq "2" ]] && continue #cpulimit is already running on this process
cpulimit -p $line -l $2
done < /tmp/tmpfile
}
while true
do
lp gnome-terminal 5
lp system-journal 5
sleep 10
done
This example limits the cpu time of each gnome-terminal instance to 5% and the cpu time of each system-journal instance to 5% as well.
I used another script I created named termsql in this example to extract the PID . You can get it here:
https://gitorious.org/termsql/termsql/source/master:
You can limit the amount of cpu time with cgroups. The OS will handle resource management just like you ask for in you question.
Here is a wiki with examples: https://wiki.archlinux.org/index.php/Cgroups
Since the processes already run as a separate user limiting all process from that user should be the easiest solution.
I see at least two options:
Use "ulimit -t" in the shell that creates your process
Use "nice" at process creation or "renice" during runtime
PS + GREP + NICE
The nice command will probably help.
This can be done using setrlimit(2) (specifically by setting RLIMIT_CPU parameter).
Throwing some sleep calls in there should force the process off the CPU for a certain time. If you sleep 30 seconds once a minute, your process shouldn't average more than 50% CPU usage during that minute.
I dont really see why you want to limit the CPU time... you should limit the total load on that machine, and the load is determined by IO operations mostly .
Ex: if i create a while(1){} loop, it will get the total load to 1.0, but if this loop does some disk writes the load jumps to 2.0... 4.0. And that's what killing your machine, not the CPU usage. The CPU usage can be easily handled by nice/renice.
Anyways, you could make a script that does a 'kill -SIGSTOP PID' for a specific PID, when the load gets too high, and kill -SIGCONT when everything gets back to normal... The PID's can be determined by using the 'px aux' command, because i see that it displays the CPU usage, and you should be able to sort the list using that column. I think this the whole thing could be done in bash...
You could scale down the CPU frequency. Then you don't have to worry about the individual processes. When you need more cpu's, scale the frequency back up.