onstat -g questions

Has anyone used the "onstat -g sch" and "onstat -g spi" commands to help tune the performance of Informix 7.1 on an SMP? If so, can you explain the exact meanings of the various columns? (I've appended excerpts from the output of these commands below.) I've read the manual, and it doesn't help to answer all my questions: 1) the sch output provides per-vp semaphore ops, spins, and busy waits; my question here is, what's a "good" or "bad" value for the number of busy waits and/or spins/wait? What trends should I expect to see? 2) the spi output "prints spin locks that vps have spun more than 10000 times to acquire... Excessive longspins might indicate an overloaded system, too many VPs,..., or an internal problem. You can reduce longspins by reducing VPs, reducing the load on the system, or using no-age or processor affinity features." My question here is, I see a very long list of spin locks with waits; Are they all longspins? Is this a problem, and if so, can it be tuned (I tried the steps suggested in the manual already)? Are the very large numbers associated with numwaits and numloops reasonable to expect? Are the names of the locks of any use in tuning? Anyone have a rough idea of the scaling seen with Informix 7.12 on relatively simple benchmarks (like debit-credit/tpcb) for small numbers of processors (2,3,4,..)? Is it any better/worse than the scaling with Informix 5? Thanks, Rajiv ------------------------ onstat -g sch output: VP Scheduler Statistics: vp pid class semops busy waits spins/wait 1 1072 cpu 0 0 0 2 1073 adm 0 0 0 3 1074 cpu 450 514 9026 4 1075 lio 2427 0 0 5 1076 pio 0 0 0 <...lines deleted...> ------------------------ onstat -g spi output: Spin locks with waits: Num Waits Num Loops Avg Loop/Wait Name 1 1 1.00 mutex lock, name = lru-2 2 2 1.00 mutex lock, name = lru-4 <...lines deleted...> 921552832 921557920 1.00 mutex waitlock, name = t_mutex 4025352228 0 0.00 mutex waitlock, name = sm_nuse 840 2002 2.38 mutex waitlock, name = netnorm 921554528 921557920 1.00 mutex waitlock, name = t_mutex 4025352228 0 0.00 mutex waitlock, name = sm_nuse <...lines deleted...> -- ---------------------------------------------------------------- Rajiv Jauhari jauhari@isd.tandem.com Performance Analysis Group phone: 512-432-8434 Tandem Computers fax: 512-432-8037 14231 Tandem Blvd., Austin, TX 78728 ----------------------------------------------------------------