RE: cpu waits

  • From: Tanel Poder <tanel.poder.003@xxxxxxx>
  • To: Luca.Canali@xxxxxxx, oracle-l@xxxxxxxxxxxxx
  • Date: Wed, 28 Feb 2007 21:56:10 +0800

When you enable OS statistics (using timed_os_statistics parameter) and your
OS + OSD implementation supports that feature then you'll see "OS Wait-cpu
(latency) time" in v$sesstat and v$sysstat which indicates the process wait
time in runqueue. This works on Solaris, don't know about others...
Luca, even if you enable resource manager, you won't see the OS CPU runqueue
waiting as far as I understand. 
The "resmgr: cpu quantum" is an artificial resource manager wait (e.g. when
a process gets on CPU it checks whether it should be on CPU per resmgr rules
and if not then it goes to sleep again and registers that wait).


From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Luca Canali
Sent: Wednesday, February 28, 2007 18:04
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: cpu waits

There is no such event, indeed it is a typical pitfall say when analysing a
statspack report on a CPU bound DB server.
The exception being when resource manager is used, then one can look at the
time spent in 'resmgr:cpu quantum'  wait event.

Other related posts: