Dual CPU's and 'top'

[gfunk123]

Hi have just built a new sunfire 280r with solaris 9 and i Have 2 questions

1) where can i view some information that will tell me for definate that the 2*900 mhz processors are both being used, i tried using "top" but it doesnt tell me for sure that both processors are churning away together

2) Our company uses SAS which is like a statistics number crunching app, when the SAS guys run a job, It is supposed to utilise the wonderful new dual 900mhz processors, but when i open "top" the SAS processes are using under 5% (if im lucky !). The interesting thing is that along the top of the "top" screen it says

CPU States -5% idle- 1% user - 3% Kernel- 95% iowait - 0% swap

can anybody tell me why iowait is at 95% and what the hell does it mean anyway !!!? . This box is running nothing but SAS and O/S associated processes, and the data it is sourcing is on the same box, so there are no NFS data access issues So why are my processes using hardly any CPU ?

any help on this would be greatly appreciated

 

[coroner74]

hi,
for 1) try 'psrinfo -v', or just 'psrinfo'
2.) that means that your process is waiting for I/O
answers. What I don't know is, what top classifies as I/O traffic. It can be the I/O on the internal busses, the network, the internal disks or the internal controllers or
everything I've forgotten now.
What I've exprienced is that top's I/O percentage is increased when high traffic on the harddiscs accour.
Hope this helps.
In my case, often expensive sql statements are made by the oracle-db that causes the high I/O traffic.
Maybe your disk-subsystem is to slow ?
Make sure the system is not swapping.
regards
coroner74

 

[bi]

In my experience, one of the main causes of high iowait when a database is involved is poor layout of the database files. If you have all the files on only one or two disks, the database is going to crawl and your iowait is going to be high. Likewise, if you have your rollbacks and redo files on the same disk or the same bus, iowait is going to be high. If you are using RAID5 for files that are write intensive, iowait is going to be high.

My version of top shows which cpu a process is using. For example:

PID USERNAME .... STATE TIME CPU ...
855 root cpu/3 66:48 1.30%
854 roo sleep 97:03 0.16%

 

[jimbopalmer]

If your database caches to RAM, then flushes to disk after a while, you will have bursts of CPU activity, then high IO Wait once everything is 'done', the database writes it all to disk once the excitement is over.

I tried to remain child-like, all I acheived was childish.

 

[tuka]

you can use prstat which will show cpu usage. See man pages
Also vmstat and mpstat are monitoring utilites. See man pages.

Solaris 9 also has Solaris Resource manager (SRM) embedded
on the media. SRM will allow you to manage your resources.
Check to see if the 280 is a supported platform by SRM.