Re: slow performance

Thuc Nguyen wrote: > > Hi > > I am running ODS 7.23 u4 on HP 10.20 > > So many users complained about slow performance...I looked at "top".... > > IDLE has been around 21% > > %WCPU 36% == (command) oninit > %CPU 35% == (command) oninit > > The partial onconfig info.... [SNIP] > SHMVIRTSIZE 135000 # initial virtual shared memory segment size > SHMADD 8192 # Size of new shared memory segments (Kbytes) Your value for SHMADD is low for an HP system. Check out onstat -g seg and see how many virtual segments (class 'V') ou have. More than 3 and your performance will plummet because the HP processors have four hardwired registers for shared memory handles. Having more than 4 causes the registers to be swapped in and out constantly which is expensive for these registers. One register is needed for the Resident segment (class 'R') so that leaves 3 for virtual segments. Increase SHMVIRTSIZE and SHMADD to prevent this. Increasing SHMADD will reduce the number of new segments needed. Monitor periodically and if you frequently have additional virtual segments fold the additional size into SHMVIRTSIZE for the next restart. This tip is useful on all platforms and will improve performance and prevent the pause that happens when a new virtual segment is added, but it is vital on HP. New HP processors planned for later this year are rumored to have solved this problem. Art S. Kagel