On Wed, Jan 02, 2013 at 09:52:37PM -0800, Kevin Oberman wrote: > On Wed, Jan 2, 2013 at 2:06 PM, Alexander Motin <m...@freebsd.org> wrote: > > On 02.01.2013 18:08, Adrian Chadd wrote: > >> > >> .. I'm pretty damned sure we're going to need to enforce a "never > >> earlier than X" latency. > > > > > > Do you mean here that we should never wake up before specified time (just as > > specified by the most of existing APIs), or that we should not allow sleep > > shorter then some value to avoid DoS? At least on x86 nanosleep(0) doesn't > > allow to block the system. Also there is already present mechanism for > > specifying minimum timer programming interval in eventtimers(9) KPI. > > I can see serious performance issues with some hardware (wireless > comes to mind) if things happen too quickly. Intuition is that it > could also play hob with VMs. > > I believe that the proper way is to wake between T_X and T_X + D. > This assumes that D is max_wake_delay, not deviation, which leaves us > at the original of (T_X) =< event_time =< (T_X + D).
i think "max delay" was the intended meaning of the D parameter. We picked bad names (tolerance, deviation,...) for it. cheers luigi _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
