On Thu, Jan 29, 2015 at 3:45 PM, John Baldwin <j...@freebsd.org> wrote: > Also, note that we always use the TSC as the cpu ticker, even if it is not the > timecounter. Thus, if C2+ is enabled on the systems, the kernel idle threads > will have an artificially low runtime since their idle time is not properly > accounted for. This does not affect any other threads as only the idle > threads "run" while the CPU is in C2+ with the TSC effectively paused. The > new default means that the idle threads will now have the proper runtime, > however.
However in a VM environment this means that runtimes for all threads can be very wrong (regardless of whether we enter C2 or lower or not). I have a coworker looking at using kvmclock in preference to TSC for the cpu ticker when the kvmclock is available. _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
