HP-UX 11i June 2001 Release Notes

General System Administration and Performance Monitoring
instant Capacity on Demand (iCOD) (updated for June 2001)
Chapter 7158
Similarly, psd_cpu_time[i] reflects the average values in
psd_mp_cpu_time[][i]. The adjustment is again to exclude the values
of deactivated processors in psd_mp_cpu_time[][i] and is then divided
by psd_proc_cnt. This eliminates taking values of deactivated
processors into account for each load average value.
Notice that even though these average fields are adjusted, no
information is lost because psd_mp_avg_*_min and psd_mp_cpu_time[]
still contain deactivated processor values.
The mpctl() changes include:
MPC_GETNUMSPUS
returns the number of activated processors, whereas
previously, the function did not check whether the
processor is deactivated before incrementing the count.
MPC_GETFIRSTSPU
returns the first activated processor.
MPC_GETNEXTSPU
returns the next activated processor and will skip
deactivated ones.
MPC_GETNUMSPUS, MPC_GETFIRSTSPU & MPC_GETNEXTSPU
take into account deactivated processors.
MPC_GETNUMSPUS
does not count deactivated processors and the other
two options will not return deactivated processors’
indices.
This is in line with the current specification of pstat and mpctl.
Prior to HP-UX 11i, the following commands incorrectly used the fields
in pstat and mpctl: top, sar, uptime, iostat, and vmstat. These
commands are fixed in HP-UX 11i in order to work correctly on iCOD
systems. These changes are only relevant to iCOD systems and systems
running the LPMC monitor in OnlineDiag; they do not affect other
systems.
Performance Issues
This feature improves performance by allowing additional parallel
processing capacity for applications when iCOD activations occur. It has
a temporary side effect of allowing additional I/O interrupt handling
capacity via the deactivated processors. This aspect changes once I/O
revectoring is implemented.