There are many different variables as output of top prstat vmstat free commands and they are depending on the OS that is used.
Which is the definition for each "major" memory variable output of the mentioned commands in order to apply as good practice investigation for memory peformance analysis?

For example : top output RES memory is the actual memory in use.

Edit 1 More over i am looking the output of the top prstat vmstat free commands the memory value meaning.


RES = Residental memory - memory in use.

SHR = Shared memory - memory segment that is shared between multiple programs the amount shown is amount of shared objects, data and libraries that program is using.

VIRT = Virtual memory(not that much useful in the memory debugging it is the size of the virtual pages that process occupy)

A bit more in depth on technical level you can find here: http://www.win.tue.nl/~aeb/linux/lk/lk-9.html

And some simpler explanation here: http://www.thegeekstuff.com/2012/02/linux-memory-management/

  • SHR is the size of the shared memory segment attached to the process. Shared memory is used to share data between processes. – Emmanuel Aug 11 '17 at 16:12

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