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 the page cannot be claimed and used by another process. |
Example—Checking Page-In Activity
The following example shows output from the sar -p command.
$ sar -p SunOS touchstone 5.9 Generic sun4u 03/04/2003 00:00:00 atch/s pgin/s ppgin/s pflt/s vflt/s slock/s 01:00:00 1.00 0.00 0.00 0.26 1.13 0.00 02:00:00 1.00 0.00 0.00 0.26 1.13 0.00 03:00:00 1.01 0.00 0.00 0.29 1.17 0.00 04:00:00 1.03 0.00 0.00 0.34 1.27 0.00 05:00:00 1.00 0.00 0.00 0.26 1.13 0.00 06:00:00 1.00 0.00 0.00 0.26 1.13 0.00 07:00:00 1.00 0.00 0.00 0.26 1.13 0.00 08:00:00 1.00 0.00 0.00 0.26 1.13 0.00 08:20:01 1.03 0.00 0.00 0.32 1.26 0.00 08:40:00 1.03 0.00 0.00 0.32 1.26 0.00 09:00:00 1.03 0.00 0.00 0.42 1.43 0.00 09:20:01 2.17 1.37 1.95 2.59 50.06 0.00 09:40:01 0.09 0.52 0.63 0.27 105.42 0.00 10:00:02 0.65 2.59 3.11 1.19 42.19 0.00 10:20:03 1.69 11.45 13.77 4.36 39.58 0.00 10:40:01 0.08 0.31 0.32 1.56 12.23 0.00 Average 1.00 0.51 0.62 0.55 8.79 0.00 |
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