>but I don't think GP meant "one process" literally. Neither that is realistic nor is it necessary. The point was simply about other processes that could be co

>but I don't think GP meant "one process" literally. Neither that is realistic nor is it necessary. The point was simply about other processes that could be competing for resources - CPU, memory, or I/O. It is expensive for a user-level process to perform accounting for all of these resources, and without such accounting you can't optimally allocate them. If there are other apps that can suddenly spike memory usage then any careful buffer tuning you've done goes out the window. Likewise for any I/O scheduling you've done, etc.