%CPU & %MEM utilization

[suresh_v_2k2]

Hi, I am trying to write a program in perl to calculate the cpu and processor utilization of a particular process (for example : mozilla). The output of the program must be just like the result obtained by ps command under linux, but i do not want to use the ps command in my program to get the cpu and memory details but use the /proc filesystem to calculate the cpu and memory utilization of process.

Can you help me how do i calculate the cpu and memory in percentage, utilized by a particular process from the /proc filesystem. I have learnt from various resources that ps command too uses /proc filesystem to get the information about processes, but i could not find any information of how to calculate the percentage utilization of cpu and memory of particular process.

I hope you could help me out of this problem.

Thank you.

[ghostdog74]

..
but i could not find any information of how to calculate the percentage utilization of cpu and memory of particular process.....

if you give the ps command the aux option, it shows %CPU and %MEM used.

# ps aux | awk 'BEGIN{ printf "%-10s%s\n","CPU","MEM"}/mozilla/{printf "%-10s%s\n",$3,$4}'
CPU       MEM
3.2       5.5
0.0       0.0

[Cabhan]

Well, /proc/meminfo has information such as the total memory of the box.

alex@danu /proc $ cat meminfo  
MemTotal:      1295048 kB
MemFree:        141768 kB
Buffers:        187912 kB
Cached:         338496 kB
SwapCached:          0 kB
...

/proc also has subdirectories for each running process. Each of these has a 'mem' file. Now, I seem to be unable to read mine, but these likely have information related to the memory usage of a particular process. If you can find a guide through /proc/PID/status, this may also have some info.

[suresh_v_2k2]

if you give the ps command the aux option, it shows %CPU and %MEM used.

# ps aux | awk 'BEGIN{ printf "%-10s%s\n","CPU","MEM"}/mozilla/{printf "%-10s%s\n",$3,$4}'
CPU       MEM
3.2       5.5
0.0       0.0

i already tried the ps command but i do not want to use ps command but to calculate my self from the information avilable in /proc/[PID]/stat or mem or cpu etc.,

any way thanks for your reply.

[suresh_v_2k2]

Well, /proc/meminfo has information such as the total memory of the box.

alex@danu /proc $ cat meminfo  
MemTotal:      1295048 kB
MemFree:        141768 kB
Buffers:        187912 kB
Cached:         338496 kB
SwapCached:          0 kB
...

/proc also has subdirectories for each running process. Each of these has a 'mem' file. Now, I seem to be unable to read mine, but these likely have information related to the memory usage of a particular process. If you can find a guide through /proc/PID/status, this may also have some info.

hi, i think you got my point. i found the information under /proc/PID/status but do you know how to i convert those values in to %values do you have any formlua to find the %cpu and %mem utilization using the values avilable in /proc/PID/stat or cpu or mem etc.,

thanks for you relpy

[Cabhan]

Alrighty, well, the proc man page has a great deal of information. In particular, it discusses the /proc/PID/stat file, where the 23rd entry is:

vsize %lu
       Virtual memory size in bytes.

If you combine that bit of information with /proc/meminfo, you should be able to figure out percentages.