Working with Event 300 (Host Resource Status)

This event applies to the application server and the Process Scheduler server.

Performance Monitor makes specific operating system calls to obtain metrics for %CPU use on the host machine, %Memory use, and the hard page fault rate. Operating systems have slightly different definitions for these quantities, and they have different ways of reporting them. In most cases, PeopleSoft expresses %Memory use to reflect utilization of physical memory.

Performance Monitor programmatically queries the Tuxedo management information base (MIB) for total Jolt connections and total requests queued. All platforms compute one or more resources as an average of the two measurements at the beginning and end of a sampling interval. Performance Monitor does not report an Event 300 (Host Resource Status) until the second sampling interval after you boot the server.

Process resource utilization is usually sampled by the operating system and written to a memory location. Windows writes to the registry, while UNIX writes to various files. The system reads the current values for the process, so events change only when the operating system updates the statistics. Most operating systems update these statistics at least once per second.

PeopleSoft obtains all information using lightweight, C++ programmatic APIs. No additional processes or shell commands are run.

Operating System Description

Windows

Performance Monitor uses Performance Data Helper (PDH) to read registry counters. The information is identical to the Windows Performance Monitor tool.

  • CPU utilization is "% Processor Time (_Total)", defined as the fraction of time not run by the system idle thread in the last PDH sampling interval (typically one second).

  • Memory utilization is "% Committed Bytes In Use" and will change if the paging file is extended by the system administrator.

  • Page faults is "Pages / sec", which reports actual disk page fetches ("Page Faults /sec" reports soft faults).

AIX

Performance Monitor uses libperfstat API (a wrapper for knlist) to read kernel counters.

  • CPU utilization is the same as "topas" and "vmstat". This is an average over the last sample period, but process CPU use is an average over process lifetime. Therefore, on AIX, it is possible for machine CPU use to be momentarily smaller than CPU use of a process that was previously CPU-intensive.

  • Memory utilization is defined as "free real pages" / "total real memory pages". The "vmstat" command shows the number of free pages, but not the available total. The "topas" field, Real MEMORY, shows "real memory pages." The PAGING SPACE field shows only reserved pages, not free pages.

  • Page faults is the same as "topas" and "vmstat", with the absolute difference averaged over the last sampling time. According to Linux information, this value includes pages faults that do not cause paging activity.

HPUX

Performance Monitor uses pstat_getdyamic (pstat) to read kernel counters.

  • CPU utilization is the same as "top" and "vmstat". This is an average over the last sample period, but process CPU use is an average over a longer time period. Therefore, it is possible on HPUX for machine CPU use to be momentarily smaller than CPU use of a process that was previously CPU-intensive.

  • Memory utilization is defined as "real memory + text pages / physical memory." Neither of these quantities are exposed with vmstat.

  • Page faults is the same as "vmstat -s, zero fill page faults", with the absolute difference averaged to a rate over the last sampling time.

Linux

Performance Monitor reads kernel statistics from files in /proc.

  • CPU utilization is the same as "top", averaged over all processors. This is an average over the last sample period.

  • Memory utilization is the same as "top", or the "free" command "Mem used / available" field. It measures physical memory utilization. The "used" field is actually "available - free". The "M" and "K" units of "top" are 1024 * 1024 bytes and 1024 bytes, respectively.

  • Page faults is the first "page" kernel counter from /proc/stat (pages swapped in from disk), with the absolute difference averaged to a rate over the last sampling time.

Solaris

Performance Monitor uses the Kernel Statistics API (kstat) to read kernel counters.

  • CPU utilization is the same as "top, user + kernel". This is an average over the last sample period, but process CPU use is a weighted average over a longer time period. Therefore, it is possible on Solaris for machine CPU use to be momentarily smaller than CPU use of a process that was previously CPU-intensive.

  • Memory utilization is defined as the "used / used + available" fields from "swap -s". This is only an approximation because of allocated but unreserved RAM. See the Sun web site for more information.

  • Page faults is the same as major page faults from "vmstat -s", with the absolute difference averaged to a rate over the last sampling time.

OS/390

Performance Monitor uses the ERBSMFI and CVT APIs to report resource use on the logical partition. Higher priority jobs on other partitions can "steal" resources and not appear in these metrics.

  • CPU utilization is the same as RMF "TOTAL/AVERAGE LPAR BUSY TIME PERC" field.

  • Memory utilization is defined from the RMF "AVAILABLE" versus RMF "TOTAL FRAMES" fields.

  • Page faults is not supported for this release.