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tuxsmouf
Asked: 2010-05-26 05:11:44 +0800 CST

The amount of memory used by each process

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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
linux memory-usage

5 Answers

  1. 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.

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  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

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  3. Top does a good job, look for these headers:

    VIRT  RES  SHR S %MEM
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  4. 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 :)

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  5. 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.

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