Messages in this thread Patch in this message | | | From | Jeremy Fitzhardinge <> | Subject | [PATCH 05/12] xen/pvclock: add monotonicity check | Date | Wed, 14 Oct 2009 12:28:29 -0700 |
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Other tsc-based clocksources add a monotonicity test to make sure there's no regression in the returned cycles.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> --- arch/x86/xen/time.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 0a5aa44..00f06cc 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -213,9 +213,14 @@ cycle_t xen_clocksource_read(void) return ret; } +static struct clocksource xen_clocksource; + static cycle_t xen_clocksource_get_cycles(struct clocksource *cs) { - return xen_clocksource_read(); + cycle_t ret = xen_clocksource_read(); + + return ret >= xen_clocksource.cycle_last ? + ret : xen_clocksource.cycle_last; } static void xen_read_wallclock(struct timespec *ts) -- 1.6.2.5
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