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Performance View V$OSSTAT

user3206995Mar 10 2011 — edited Mar 12 2011
I am trying to understand the busy_time column in the v$osstat view.

I took a before and snap of this view.

VALUE STAT_NAME
---------- ----------------------------------------------------------------
64 NUM_CPUS
7776667365 IDLE_TIME
357220150 BUSY_TIME
159550984 USER_TIME
197669166 SYS_TIME
0 IOWAIT_TIME
121468398 AVG_IDLE_TIME
5539550 AVG_BUSY_TIME
2451063 AVG_USER_TIME
3046655 AVG_SYS_TIME
0 AVG_IOWAIT_TIME
11140800 OS_CPU_WAIT_TIME
0 RSRC_MGR_CPU_WAIT_TIME
5.10546875 LOAD
8 NUM_CPU_CORES
1 NUM_CPU_SOCKETS
6.8585E+10 PHYSICAL_MEMORY_BYTES
1.6960E+10 VM_IN_BYTES
8192 VM_OUT_BYTES
49152 TCP_SEND_SIZE_DEFAULT
1048576 TCP_SEND_SIZE_MAX
49152 TCP_RECEIVE_SIZE_DEFAULT
1048576 TCP_RECEIVE_SIZE_MAX


After :

VALUE STAT_NAME
---------- ----------------------------------------------------------------
64 NUM_CPUS
7814976860 IDLE_TIME
360357230 BUSY_TIME
160430595 USER_TIME
199926635 SYS_TIME
0 IOWAIT_TIME
122066763 AVG_IDLE_TIME
5588356 AVG_BUSY_TIME
2464596 AVG_USER_TIME
3081702 AVG_SYS_TIME
0 AVG_IOWAIT_TIME
11206700 OS_CPU_WAIT_TIME
0 RSRC_MGR_CPU_WAIT_TIME
5.21484375 LOAD
8 NUM_CPU_CORES
1 NUM_CPU_SOCKETS
6.8585E+10 PHYSICAL_MEMORY_BYTES
1.7078E+10 VM_IN_BYTES
8192 VM_OUT_BYTES
49152 TCP_SEND_SIZE_DEFAULT
1048576 TCP_SEND_SIZE_MAX
49152 TCP_RECEIVE_SIZE_DEFAULT
1048576 TCP_RECEIVE_SIZE_MAX


I had elapsed time of 5Mins

I now attempted to calculate the system CPU Utilization over this period.

I am using hyperthreading which gives me 64 CPUs


My calculation is:
substract After busy_time - Before busy_time

36035723 - 357220150 = 3137080 hundredeths of a sec

available CPU time 64 * 5*60 = 19200 secs

now I am trying to calculate CPU Utilization

U=R/C 31370.80/19200 = 1.63 or 163%.

Is this possible or is my calculation incorrect ?

Thank you in adavnce
u
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Locked on Apr 9 2011
Added on Mar 10 2011
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