I have to display the CPU usage on my application and update it in real time. I am using top command to get the CPU usage i.e.
I add the two highlighted values to get the CPU usage. The command which i am using to add the highlighted values and get the final CPU usage is:
top -b -n 2 | grep Cpu | awk '{printf "CPU Load:%.2f\n", $(NF-13) + $(NF-15)}' | sed -n '2 p'
Issues is that, this command stops working after sometime i.e. for 3-4 minutes i do get the CPU usage but after that command does not process and i do not get the updated value. I am running this command in a loop.
Any help would be much appreciated.
I am using the similar script without issues for some time now:
top -bn2 | grep Cpu | tail -n1 | sed -e 's/.*, *\([0-9.]*\)%* id.*/\1/' | awk '{print 100-$1}'
The script takes the 'idle' time from top output and deduct it from 100% to get cpu usage.
The periodicity of the loop in which you are calling the script should not be faster than the time needed for the script to finish. Otherwise, you may get multiple 'top's running in parallel. This primarily depends on the 'top' default delay on your system, on mine, it is about 5s, but you can set this with -d switch.
I want to get top command result of a specific process and then save it in a file.
I tried the following command:
top | grep "qemu" > file
but this doesn't work.
How can I implement this?
Use the -b and -n command line options:
top -bn1 | grep qemu > file
From man top:
-b :Batch-mode operation
Starts top in 'Batch' mode, which could be useful for sending output from top to other programs or to a file.
In this mode, top will not accept input and runs until the iterations limit you've set with the '-n' com‐
mand-line option or until killed.
-n :Number-of-iterations limit as: -n number
Specifies the maximum number of iterations, or frames, top should produce before ending.
Try this :
top -b -p `pgrep -d, -f qemu` > top-output.txt
-b : Batch mode operation
Starts top in "Batch mode", which could be useful for sending out-
put from top to other programs or to a file. In this mode, top
will not accept input and runs until the iterations limit youâve
set with the â-nâ command-line option or until killed.
I got a simple script (to measure CPU overhead)
#!/bin/bash
WAIT=2
i=1
while :
do
# Obtain the cpu usage
top -n 1 > t.$i
i=$(($i+1))
sleep $WAIT
done
When I run it as
./Script.sh
It works as expected.
But when I run it as
./Script.sh&
it does nothing (files are not created). What am I missing here?
Change the line where you invoke top to be:
top -b -n 1 > t.$i
This enables batch mode - good call Karoly
I am new to Perl. I am working on a web UI where I have to give CPU and memory monitoring data, so I am using top and gnuplot command. I am able to do it through my terminal. but when I am executing same commands with a perl script its not working. The problem I am having is that whenever I am executing top command in my terminal than I have to wait for few minutes and then I have to plot it using GNUPLOT but when I am doing the same work using system command in perl I am unable to give that delay.
Here is what I am doing
system "top -p 1758 -b -d5 | tee -a stats.log";
system "./top_stats.sh -f stats.log"
Here 1758 is the app ID whose top data I have to monitor and stats.log file is the one where I am saving logs and then using this stats.log file as input to top_stats.sh script I am plotting graphs. This top_stats.sh script takes the log file and uses gnuplot to plot data
Now the problem is whenever I am executing this first system command in terminal I have to wait for some time say 2 to 3 minutes to have ample number of data points and then I have to press Ctrl+C to come out of top command and then run the script. but here as soon as this first system command is encountered it is executed and then next command is executed without any delay so I am not getting any data points to plot the graph. Is there any way I can execute my first command and wait for 3 minutes without coming out of system command and then execute the next command.??
Is there any way I can execute my first command and wait for 3 minutes without coming out of system command and then execute the next command.??
Why not specify the number of iteration for top. So your command will rougly run for (N-1)*5 seconsds. 37 iterations with an interval of 5 seconds are going to take 36*5 seconds:
system "top -p 1758 -b -d5 -n37 | tee -a stats.log && ./top_stats.sh -f stats.log";
Is there any ready-to-use solution to log the memory consumption from the start of the system? I'd like to log the data to simple text file or some database so I can analyze it later.
I'm working on Linux 2.4-based embedded system. I need to debug the problem related to memory consumption. My application automatically start on every system start. I need the way to get the data with timestamps from regular intervals (as often as possible), so I can track down problem.
The symptoms of my problem: when system starts it launched my main application and GUI to visualize the main parameters of the system. GUI based on GTK+ (X server). If I disable GUI and X server then my application works OK. If I enable GUI and X server it does not work when I have 256 MiB or 512 MiB of physical memory installed on the motherboard. If I have 1 GiB of memory installed then everything is OK.
The following script prints time stamps and a header.
#!/bin/bash -e
echo " date time $(free -m | grep total | sed -E 's/^ (.*)/\1/g')"
while true; do
echo "$(date '+%Y-%m-%d %H:%M:%S') $(free -m | grep Mem: | sed 's/Mem://g')"
sleep 1
done
The output looks like this (tested on Ubuntu 15.04, 64-bit).
date time total used free shared buffers cached
2015-08-01 13:57:27 24002 13283 10718 522 693 2308
2015-08-01 13:57:28 24002 13321 10680 522 693 2308
2015-08-01 13:57:29 24002 13355 10646 522 693 2308
2015-08-01 13:57:30 24002 13353 10648 522 693 2308
A small script like
rm memory.log
while true; do free >> memory.log; sleep 1; done
I am a big fan of logging everything and I find it useful to know which processes are using the memory and how much each process is using (as well as sumary statistics). The following command records a top printout ordered by memory consumption every 0.5 seconds:
top -bd0.5 -o +%MEM > memory.log
Just note that the log file will grow a lot faster than if you only store the total memory utilization statistics so be sure you don't run out of disk space.
There's a program called
sar
on *nix systems. You could try to use that to monitor memory usage. It takes measurements at regular intervals. Do a
man sar
for more details. I think the option is -r for taking memory measurements, -i to specify the interval you'd like.
I think adding a crontab entry will be enough
*/5 * * * * free -m >> some_output_file
There are other tools like SeaLion, New Relic, Server Density etc which will almost do the same but are much easier to install and configure. My favorite is SeaLion, as it being free and also it gives a awesome timeline view of raw outputs of common linux commands.
You could put something like
vmstat X >> mylogfile
into a startup script. Since your application is already in startup you could just add this line to the end of the initialization script your application is already using.
(where X is # of seconds between log messages)
To periodically log the memory usage efficiently, I combined another answer here with a method to only retain the top-K memory-using processes.
top -bd 1.5 -o +%MEM | grep "load average" -A 9 > memory_usage.log
This command will record, every 1.5s, the top header information and the 3 highest memory-consuming processes (there's a 6-line offset for top's header information). This saves lots of disk space over recording top's information for every process.
So I know that I am late to this game, but I just came up with this answer, as I needed to do this, and really didn't want the extra fields that vmstat, free, etc... all will seem to output without excess filtering. So here is the answer that I came up with:
top -bd 0.1 | grep 'KiB Mem' | cut -d' ' -f10 > memory.txt
OR:
top -bd 0.1 | grep 'KiB Mem' | cut -d' ' -f10 | tee memory.txt
the standard output from top when grep ing with Kib Mem is:
KiB Mem : 16047368 total, 8708172 free, 6015720 used, 1323476 buff/cache
By running this through cut, we filter down to literally just the number prior to used
The user can indeed modify the 0.1 to another number in order to run different capture sample rates. In my case I wanted to use top also because you can run memory stats faster than 1 second per capture, as you can see here I wanted to capture a stat every 1/10th of a second.
NOTES:
It does turn out that piping through cut cause MASSIVE delay in getting anything out to file. As we later found out, it is much faster to leave out the cut command during data acquisition, then perform the cut command on the output file later.
Also, we had no need for timestamps in our tests.
This thus looks as follows:
Begin Logging:
top -bd 0.1 | grep 'KiB Mem' | tee memory_raw.txt
Exit Logging:
ctrl-z (to exit logging)
Filter:
2 levels of cut (filtering), first by comma, then by space. This is due to the alignment of top and provides much cleaner output:
cut memory_raw -d',' -f3 | tee memory_used_withlabel.txt
cut memory_used_withlabel.txt -d' ' -f3 | tee memory_used.txt