05-01-2004 12:55 PM
We have following set-up
HP-UX 11i 64 Bit
Oracle database 220.127.116.11
Oracle application 11.5.9
we observed that out usr+cpu usage is quite high almost 100%. sys cpu ranges from 20-70% at times and on average 50%.
Does anybody know why system cpu is very high. I am skeptical about slow I/O since we are using eva5000 2c6d for storage.
05-01-2004 03:40 PM
2) Collect some data with the script I'm attaching. It might not be oracle(yeah right).
Owner of ISN Corporation
05-01-2004 04:22 PM
do ? to see different options and q to quit.
05-02-2004 12:31 PM
Top doen't show break down of CPU by individual process as [User+Sys]. Is it common behaviour for System CPU to be as high this. I had not seen this behaviour in HP-UX 11.00 with Oracle database 18.104.22.168 and Oracle Application 11.5.4. Can we establish that this kind of "SYS cpu" Usage is abnormal?
05-02-2004 03:14 PM
Just to muddy things up a bit, if the applications are always accessing the same area of disk, the EVA storage array may always have the data in buffer RAM and therefore disk response would appear to be in the sub-millisecond range. That would mean that thosands of I/Os could be performed per second, which implies that the driver is very busy and therefore the kernel would show high system usage. You need to check on the I/O count to see if that's the case.
05-29-2004 03:35 AM
o We saw high sys CPU when we were using kernel asynchronous IO on a V-class (lots of CPU) HP-UX 11.0 though
o High sys cpu activity is usually associated with high IO activity. This may not necessarily mean the disks (or network etc) are slow, but merely that they are being used badly. e.g. unnecessary sequential scans, continously reading static information into & out of memory, etc.
05-29-2004 10:21 AM
Some thing to add on, you should also look at the memory usage and swapping on the system. If the real memory is too low and system started to paging out to the disks, that could also slwo down things and eat up a good amount of cpu cycles..
vmstat should be your buddy here.