How Is "memory paging" activity calculated by the cdm probe?

Document ID : KB000034683
Last Modified Date : 14/02/2018
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Question:

How Is "Memory Paging" Activity Calculated by the cdm probe?

Answer:  

The cdm probe uses paging in KB/s as its base measurement, and it knows the pagesize so it can also make pages/sec as shown here in this image from the advanced tab of the cdm probe configuration GUI.

User-added image

The formula is:

Paging_kbps = (paging * pagesize) / seconds.

The data collection method is dependent on the operating system:

AIX
: run /usr/bin/vmstat. Read pi and po counters.

HP: run pstat_getvminfo() function. Read psv_spgin and psv_spgout counters from the struct pst_vminfo.

Linux: Depending on the version of the kernel. 2.6 or newer kernels read /proc/vmstat and read the pswp counter. Pre-2.6 kernels read /proc/stat and read the first two swap counters.
Note: counters are cumulative, so you must diff since last run!

SGI: run sysmp() function. Read swapin and swapout counters from the struct sysinfo.
Note: counters are cumulative, so you must diff since last run!

Solaris: run /usr/bin/vmstat –s. Read pages paged in and pages paged out counters.
Note: counters are cumulative, so you must diff since last run!

Tru64: run vm_statistics() function. Read the pageins and pageouts counters from the struct vm_statistics.
Note: counters are cumulative, so you must diff since last run!

Windows: Read Pages/sec counter in Memory subsystem of the performance registry