Messages in this thread | | | From | Peter Chubb <> | Date | Thu, 30 Oct 2003 09:50:38 +1100 | Subject | Re: gettimeofday resolution seriously degraded in test9 |
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>>>>> "Stephen" == Stephen Hemminger <shemminger@osdl.org> writes:
Stephen> On Wed, 29 Oct 2003 11:07:45 +0100 Gabriel Paubert Stephen> <paubert@iram.es> wrote: >> for example.
Stephen> The suggestion of using time interpolation (like ia64) would Stephen> make the discontinuities smaller, but still relying on fine Stephen> grain gettimeofday for controlling servo loops with NTP Stephen> running seems risky. Perhaps what you want to use is the Stephen> monotonic_clock which gives better resolution (nanoseconds) Stephen> and doesn't get hit by NTP.
monotonic_clock: -- isn't implemented for most architectures -- even for X86 only works for some timing sources -- and for the most common case is variable rate because of power management functions changing the TSC clock rate.
As far as I know, there isn't a constant-rate monotonic clock available at present for all architectures in the linux kernel. The nearest thing is scheduler_clock().
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