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authorThomas Gleixner <tglx@linutronix.de>2015-04-15 00:08:37 +0300
committerThomas Gleixner <tglx@linutronix.de>2015-04-22 18:06:49 +0300
commit868a3e915f7f5eba8f8cb4f7da2276760807c51c (patch)
treedcec10d02c9613b5cad4f32d6d3ed7352825b1c8 /include/linux/timekeeper_internal.h
parent21d6d52a1b7028e6a6840bd82e354aefa9a5e203 (diff)
downloadlinux-868a3e915f7f5eba8f8cb4f7da2276760807c51c.tar.xz
hrtimer: Make offset update smarter
On every tick/hrtimer interrupt we update the offset variables of the clock bases. That's silly because these offsets change very seldom. Add a sequence counter to the time keeping code which keeps track of the offset updates (clock_was_set()). Have a sequence cache in the hrtimer cpu bases to evaluate whether the offsets must be updated or not. This allows us later to avoid pointless cacheline pollution. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20150414203501.132820245@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'include/linux/timekeeper_internal.h')
-rw-r--r--include/linux/timekeeper_internal.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index fb86963859c7..6f8276ae579c 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -49,6 +49,7 @@ struct tk_read_base {
* @offs_boot: Offset clock monotonic -> clock boottime
* @offs_tai: Offset clock monotonic -> clock tai
* @tai_offset: The current UTC to TAI offset in seconds
+ * @clock_was_set_seq: The sequence number of clock was set events
* @raw_time: Monotonic raw base time in timespec64 format
* @cycle_interval: Number of clock cycles in one NTP interval
* @xtime_interval: Number of clock shifted nano seconds in one NTP
@@ -85,6 +86,7 @@ struct timekeeper {
ktime_t offs_boot;
ktime_t offs_tai;
s32 tai_offset;
+ unsigned int clock_was_set_seq;
struct timespec64 raw_time;
/* The following members are for timekeeping internal use */