RE: CPU VP's
>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??). If you are using Solaris you can tell the OS to ignore the other 4 CPUs and just not use them, and AFAIR, you can do the same thing under AIX. I'm not too sure why you would want to thought unless you are doing a scaling exercise. Paul Watson # WFSoftware Ltd # It said it needed Win95 Tel: +44 1436 674729 # or better Fax: +44 1436 678693 # so I used Unix www.wfsoftware.com/informix #
Paul Watson wrote: > > >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??). > > If you are using Solaris you can tell the OS to ignore the other 4 CPUs > and just not use them, and AFAIR, you can do the same thing under AIX. > I'm not too sure why you would want to thought unless you are doing > a scaling exercise. Some UNIXs also have a CPUMASK or similar kernel parameter that restricts access to the first N CPUs to system processes so that user processes do not hamper the activity of OS and other important processes. Then there is a set of system calls that a process can execute to register permission to run on the restricted CPUs so you can develop high priority apps and servers for your environment. We use this feature to run our proprietary IPC servers on the first 4 CPUs with OS functions restricting DB and application servers and tasks to the remaining CPUs. Art S. Kagel