Eric Saxe wrote: > Hi Bill, > > Bill Holler wrote: > >> Is there any other speedup we can do to reduce HPET scheduling? >> >> The current implementation only programs the HPET for the >> next lAPIC interrupt that would fire. The HPET is not accessed >> when later lAPIC interrupt are "scheduled" onto the HPET until. >> >> > Just to make sure I understand... > What happens in the current implementation when multiple CPUs enter a > deep c-state. Im guessing that the earliest request wakeup winds up > being what the HPET is programmed for, and then in the context of that > interrupt you re-program the HPET to interrupt to expire the later request? >
Yes. The scenario you described is correct. Additionally the interrupt service routine interrupts all CPUs that have expired at the time the ISR is running. It is possible for multiple CPUs to expire at the same time, or at least by the time the HPET's ISR runs. poke_cpu() is used to send the IPI because of its low overhead. Thanks, Bill > Thanks, > -Eric > _______________________________________________ > tesla-dev mailing list > tesla-dev at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/tesla-dev >
