monline

There's already a good answer to the question at stackoverflow. They suggested to use the top command, then change the sorting field to "swap" by hitting O and p. Unfortunately (afaik) there's no way to do this in batch mode (using the -b switch) and save the top swap using prorcesses in a file. There's another method: use the ps command.

The "swap" field of top is described by the manpage as: "The swapped out portion of a task’s total virtual memory image."

The "vsz" field of ps is described by the manpage as: "virtual memory size of the process in KiB (1024-byte units). Device mappings are currently excluded; this is subject to change."
The "rss" field of ps is described by the manpage as: "resident set size, the non-swapped physical memory that a task has used (in kiloBytes)."

The difference of "vsz" and "rss" should provide the swap usage. The result from this formula is almost equal to the values in the "swap" field of the top command (the discrepancy is minimal).

P.S.: I've turned this ps processing command into a shell script (see the attachment of this post) that you can use (eg. through crontab) to periodically log the top swap using processes (with the -s switch of the script) or the top physical memory using processes (this is the default).

Attachment	Size
process_memory_monitor.sh	1.94 KB