Hi, With the timekeeping going to be maintained by full system idle detection patchset from Paul, it seems that the guarantees that enforce timekeeping progression are going to grow in complexity enough to deserve some automated checking.
So here is a proposition in the form of a timekeeping watchdog. It uses periodic NMIs that poll on any suspicious drift between jiffies and a global cpu clock progression. Thanks. Frederic Weisbecker (6): sched: Let arch tell us if sched clock is NMI-safe x86: nsecs to cycles conversion x86: Tell that sched clock is callable in nmi seqlock: Add raw_seqbegin() for non-waiting readers jiffies: Add jiffies_to_nsecs timekeeping: Debug missing timekeeping updates arch/Kconfig | 8 ++ arch/x86/Kconfig | 2 + arch/x86/include/asm/cycles.h | 11 +++ arch/x86/kernel/apic/hw_nmi.c | 7 -- include/linux/jiffies.h | 6 ++ include/linux/seqlock.h | 5 ++ include/linux/time.h | 11 +++ kernel/time/Makefile | 1 + kernel/time/tick-sched.c | 4 + kernel/time/timekeeping.c | 1 + kernel/time/timekeeping_selftest.c | 125 ++++++++++++++++++++++++++++++++++++ kernel/watchdog.c | 3 +- lib/Kconfig.debug | 13 ++++ 13 files changed, 189 insertions(+), 8 deletions(-) create mode 100644 arch/x86/include/asm/cycles.h create mode 100644 kernel/time/timekeeping_selftest.c -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
