Re: CPU VP's

From: Bridget Reitsma <b.reitsma@auckland.ac.nz> > >What is the rule of thumb regarding the number of CPU VP's. One per CPU > >and not more than the total of CPU's on the machine? And how does this >tie in with 'a virtual processor is a piece of work for a CPU' Admin >Guide for Informix Dynamic Server pg 9-5. If my understanding of this >statement is correct I need to work out the optimal figure of how many >CPU Vp's can run on a CPU?! Well, I've had a fairly calm and reasoned debate with someone from ATG about this, and while I can see their point of view, empirical evidence seems to show that if you are running on quite quick CPUs, you can have more than one VP per CPU. Officialy, you can have at most one per CPU. >Also I want ensure that only 4 physical CPU's are used (for everything >and there are 8 on the box) but I don't want to bind any process to a >certain CPU (I have already set the numcpuvps 4 but I also have 2 >aiovps) . If I use the parameter AFF_NPROCS - this specifies the number >of CPU's (but does this mean affinity is switched on or is it only on >when I use this parameter in conjunction with >AFF_SPROCS??). AFAIK, AFF_NPROCS and AFF_SPROCS must be used in conjunction, or they do nothing. What affinity does is say "don't run on any other CPU", it doesn't say "don't run anything else on this CPU". ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com