1

I have a mysql server running debian with 2GO of RAM. I would like to know the amount of memory used by each process.

I thought ps -aux was the command and options for it. But I only see 90 MO used by several processes and free -m tells me that 1400 MO are used.

Is there a way to have a better view with the processes and the memory used by them ?

srv-datax:~# free -m
             total       used       free     shared    buffers     cached
Mem:          2015       1476        539          0          0         70
-/+ buffers/cache:       1405        609
Swap:          486          0        486
Improve this question

5 Answers 5

Reset to default
2

You should post your free output so we know you are reading is correctly. Memory usage on Linux for a process is hard to nail down specifically, if you really want to get into the details and have a recent kernel, check cat /proc/<pid>/smaps.

Improve this answer
2 
#top

is a good option

#top -H

lets you monitor all Threads

#top -U root

this kind of using '-U' switch lets you monitor user-specific listing

Improve this answer
0

Top does a good job, look for these headers:

VIRT  RES  SHR S %MEM
Improve this answer
1
  • srv-datax:~# free -m total used free shared buffers cached Mem: 2015 1476 539 0 0 70 -/+ buffers/cache: 1405 609 Swap: 486 0 486
    – tuxsmouf
    May 25, 2010 at 13:30
0

Another option along the same lines as what AbhishekKr suggested: ps aux will give you a breakdown of the memory used by every process on the system.

VSZ => Virtual Size (physical RAM+swap used), RSS => Resident Size (physical RAM only).
The %MEM column reflects the % of physical RAM used if memory serves, I'm sure someone will correct me if I'm wrong :)

Improve this answer
3
  • 1
    The problem is those are kind of messed up, they don't properly account for shared memory, so if you have a bunch of instances of a program, it will show that memory over and over again. The end result being that summed RSS overestimates memory.
    – Kyle Brandt
    May 25, 2010 at 18:24
  • For example: ps -A -o rss,cmd | grep oracle | awk '{print $1}' | (tr '\n' '+'; echo 0) | bc returns 12733324, where as free -buffers/cache is 1741736
    – Kyle Brandt
    May 25, 2010 at 18:28
  • That's true: ps includes shared memory in RSZ. If you're summing up the data this can lead to over-counting, but it's still a good indicator of rough size for a single process if you don't mind that fuzz. If you want to exclude shared pages top's output is probably better as it lists shared memory separately.
    – voretaq7
    May 25, 2010 at 19:03
0

Adding to what Kyle Brandt suggested, you could use the Tool pmap which nicely summarizes the information found in /proc/<pid>/smap. If you use the -d option, it will show you how much memory is mapped, shared and set private. This, IMHO, provides a good view.

I can also suggest reading this interesting article about memory usage.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .