Assuming that the "cycles" are fundamental CPU cycles (as opposed to
memory accesses, or something), that could take 1 microsecond or less
(depending on your clock speed), which isn't much. Even better, if
you arrange that the kernel doesn't use either FP or MMX, then MMX/FP
switches can only happen when switching user processes, which is
fairly infrequent -- and the MMX/FP switchover overhead is probably
much smaller than the scheduler overhead.
Dale
-- Dale R. Worley Ariadne Internet Services Voice: +1 617-899-7949 Fax: +1 617-899-7946 E-mail: worley@ariadne.com "Internet-based electronic commerce solutions to real business problems."