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| author | Thomas Gleixner <tglx@linutronix.de> | 2015-04-14 21:08:37 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-04-22 17:06:49 +0200 |
| commit | 868a3e915f7f5eba8f8cb4f7da2276760807c51c (patch) | |
| tree | dcec10d02c9613b5cad4f32d6d3ed7352825b1c8 /include/linux/timekeeper_internal.h | |
| parent | 21d6d52a1b7028e6a6840bd82e354aefa9a5e203 (diff) | |
| download | lwn-868a3e915f7f5eba8f8cb4f7da2276760807c51c.tar.gz lwn-868a3e915f7f5eba8f8cb4f7da2276760807c51c.zip | |
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.h | 2 |
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 */ |