How to Check Page-In Activity (sar -p) (System Administration Guide: Advanced Administration)

System Administration Guide: Advanced Administration

How to Check Page-In Activity (`sar -p`)

Use the sar -p command to report page-in activity which includes protection and translation faults.

$ sar -p
00:00:00  atch/s  pgin/s ppgin/s  pflt/s  vflt/s slock/s
01:00:00    0.07    0.00    0.00    0.21    0.39    0.00

The following table describes the reported statistics from the -p option.

Table 24–14 Output From the sar -p Command


Field Name	Description
`atch/s`	The number of page faults, per second, that are satisfied by reclaiming a page currently in memory (attaches per second). Instances include reclaiming an invalid page from the free list and sharing a page of text that is currently being used by another process (for example, two or more processes that are accessing the same program text).
`pgin/s`	The number of times, per second, that file systems receive page-in requests.
`ppgin/s`	The number of pages paged in, per second. A single page-in request, such as a soft-lock request (see `slock/s`), or a large block size, might involve paging-in multiple pages.
`pflt/s`	The number of page faults from protection errors. Instances of protection faults are illegal access to a page and “copy-on-writes.” Generally, this number consists primarily of “copy-on-writes.”
`vflt/s`	The number of address translation page faults, per second. These faults are known as validity faults, and occur when a valid process table entry does not exist for a given virtual address.
`slock/s`	The number of faults, per second, caused by software lock requests that require physical I/O. An example of the occurrence of a soft-lock request is the transfer of data from a disk to memory. The system locks the page that is to receive the data, so that it cannot be claimed and used by another process.

Example—Checking Page-In Activity

The following abbreviated example shows output from the sar -p command.

$ sar -p
SunOS venus 5.9 Generic sun4u    06/24/2001

00:00:00  atch/s  pgin/s ppgin/s  pflt/s  vflt/s slock/s
01:00:00    0.07    0.00    0.00    0.21    0.39    0.00
02:00:02    0.07    0.00    0.00    0.21    0.39    0.00
03:00:00    0.32    0.00    0.00    1.10    2.48    0.00
04:00:00    0.09    0.00    0.00    0.32    0.57    0.00
05:00:01    0.07    0.00    0.00    0.21    0.39    0.00
06:00:00    0.07    0.00    0.00    0.21    0.39    0.00

Average     0.26    0.20    0.30    0.92    1.78    0.00