Re: Opinions on usercpu & syscpu in onstat -p

Darren_Jacobs@carmax.com wrote: > Just wanted to get some opinions on the usercpu and syscpu meaning in the > onstat -p output. I can't remember if I read in Lumbley's guide or not,> but if usercpu exceeds the amount of lapsed time this indicates the system > could benefit from more physical cpus. Below is an onstat -p output where > total elapsed time is 67740 seconds. User cpu more than twice that at > 150,951 Unless you zero'd out the stats 18:49:00 ago the system's been online for 2days 20:32:50 which amounts to: 2 * 86400 + 20 * 3600 + 32 * 60 + 50 seconds or 246770 seconds which is much more than 150591.57. Besides I don't buy the argument. If you want to check that kind of resource utilization, here's how I'd do the calculation. How many CPU VPs are you runnning? If it's less than six (number of physical CPUs) then you can be taking better advantage of the CPUS you already have before buying more unless there is a significant CPU drain from other applications (which you must of course consider). Beyond that, on any given day you could use up to 86400 * NUMCPUVPS seconds of CPU time and no more. Now if you were getting closer that about half that theoretical max then yes you will gain from more CPU VPs in terms of headroom before you are seriously affected by running out of CPU resources. On the other hand I'm not convinced that this is a valid calculation to make in the sense that EVEN if you are only using 25% of capacity that does not mean that additional CPUS would not improve response time for that once a day query that's taking 30 minutes to run and could be better parallelized if you have more CPUS and completed in 15 minutes or less instead. Art S. Kagel > HP N Class 6 Way 550's > 6 gig Physical Mem. > HPUX 11 > 9.40 FC2 > > > IBM Informix Dynamic Server Version 9.40.FC2W4 -- On-Line -- Up 2 days > 20:32:50 -- 3918780 Kbytes> > Profile > dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached > 58767865 124325277 12739374150 99.54 4592164 31893241 24004499 80.87 > > isamtot open start read write rewrite delete commit > rollbk > 7825834138 6479678 83176707 6822458070 178820294 1276025 720792 80860 > 488 > > gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs > 0 0 0 0 0 0 0 > > ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes > 0 0 0 150951.57 5282.00 143 429 > > bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans > 3446881 2048 12220794081 23 0 512 480281 5784056 > > ixda-RA idx-RA da-RA RA-pgsused lchwaits > 13697305 1729291 18192868 33137079 94700177 > > > sending to informix-list