#include <kern/clock.h> clock_get_uptime is in CPU cycles. clock_get_system_nanotime() is in nanoseconds. Just check the header out there is a whole lot of APIs in there for. You can get access to the counters using the CHUD framework, check out the developer's website for details. Are you in IOKit space? Godfrey On 2004 Mar 31, at 7:27, Lamont Cranston wrote: Is there any way to get a high resolution system uptime in nanoseconds or in number of CPU cycles? Also, I am interested in gathering CPU utilization statistics and number of interrupts during I/O. Is there any method of doing this? Can the PMC registers be used? If so, is there any documentation on how to program the MMCR registers? Should one use the processor_control() method (mach/processor.h, mach/ppc/processor_info.h) to do this? _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.