From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Marcelo Tosatti <mtosatt@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
John Stultz <john.stultz@linaro.org>
Subject: [patch 08/39] hrtimer: Make offset update smarter
Date: Tue, 14 Apr 2015 21:08:37 -0000 [thread overview]
Message-ID: <20150414203501.132820245@linutronix.de> (raw)
In-Reply-To: 20150414203303.702062272@linutronix.de
[-- Attachment #1: hrtimer-make-offset-update-smarter.patch --]
[-- Type: text/plain, Size: 5744 bytes --]
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>
Cc: John Stultz <john.stultz@linaro.org>
---
include/linux/hrtimer.h | 4 ++--
include/linux/timekeeper_internal.h | 2 ++
kernel/time/hrtimer.c | 3 ++-
kernel/time/timekeeping.c | 23 ++++++++++++++++-------
kernel/time/timekeeping.h | 7 ++++---
5 files changed, 26 insertions(+), 13 deletions(-)
Index: tip/include/linux/hrtimer.h
===================================================================
--- tip.orig/include/linux/hrtimer.h
+++ tip/include/linux/hrtimer.h
@@ -163,7 +163,7 @@ enum hrtimer_base_type {
* and timers
* @cpu: cpu number
* @active_bases: Bitfield to mark bases with active timers
- * @clock_was_set: Indicates that clock was set from irq context.
+ * @clock_was_set_seq: Sequence counter of clock was set events
* @expires_next: absolute time of the next event which was scheduled
* via clock_set_next_event()
* @in_hrtirq: hrtimer_interrupt() is currently executing
@@ -179,7 +179,7 @@ struct hrtimer_cpu_base {
raw_spinlock_t lock;
unsigned int cpu;
unsigned int active_bases;
- unsigned int clock_was_set;
+ unsigned int clock_was_set_seq;
#ifdef CONFIG_HIGH_RES_TIMERS
ktime_t expires_next;
int in_hrtirq;
Index: tip/include/linux/timekeeper_internal.h
===================================================================
--- tip.orig/include/linux/timekeeper_internal.h
+++ tip/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 */
Index: tip/kernel/time/hrtimer.c
===================================================================
--- tip.orig/kernel/time/hrtimer.c
+++ tip/kernel/time/hrtimer.c
@@ -451,7 +451,8 @@ static inline ktime_t hrtimer_update_bas
ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
- return ktime_get_update_offsets_now(offs_real, offs_boot, offs_tai);
+ return ktime_get_update_offsets_now(&base->clock_was_set_seq,
+ offs_real, offs_boot, offs_tai);
}
/* High resolution timer related functions */
Index: tip/kernel/time/timekeeping.c
===================================================================
--- tip.orig/kernel/time/timekeeping.c
+++ tip/kernel/time/timekeeping.c
@@ -602,6 +602,9 @@ static void timekeeping_update(struct ti
update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
+
+ if (action & TK_CLOCK_WAS_SET)
+ tk->clock_was_set_seq++;
}
/**
@@ -1927,15 +1930,19 @@ void do_timer(unsigned long ticks)
/**
* ktime_get_update_offsets_now - hrtimer helper
+ * @cwsseq: pointer to check and store the clock was set sequence number
* @offs_real: pointer to storage for monotonic -> realtime offset
* @offs_boot: pointer to storage for monotonic -> boottime offset
* @offs_tai: pointer to storage for monotonic -> clock tai offset
*
- * Returns current monotonic time and updates the offsets
+ * Returns current monotonic time and updates the offsets if the
+ * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
+ * different.
+ *
* Called from hrtimer_interrupt() or retrigger_next_event()
*/
-ktime_t ktime_get_update_offsets_now(ktime_t *offs_real, ktime_t *offs_boot,
- ktime_t *offs_tai)
+ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
+ ktime_t *offs_boot, ktime_t *offs_tai)
{
struct timekeeper *tk = &tk_core.timekeeper;
unsigned int seq;
@@ -1947,10 +1954,12 @@ ktime_t ktime_get_update_offsets_now(kti
base = tk->tkr_mono.base;
nsecs = timekeeping_get_ns(&tk->tkr_mono);
-
- *offs_real = tk->offs_real;
- *offs_boot = tk->offs_boot;
- *offs_tai = tk->offs_tai;
+ if (*cwsseq != tk->clock_was_set_seq) {
+ *cwsseq = tk->clock_was_set_seq;
+ *offs_real = tk->offs_real;
+ *offs_boot = tk->offs_boot;
+ *offs_tai = tk->offs_tai;
+ }
} while (read_seqcount_retry(&tk_core.seq, seq));
return ktime_add_ns(base, nsecs);
Index: tip/kernel/time/timekeeping.h
===================================================================
--- tip.orig/kernel/time/timekeeping.h
+++ tip/kernel/time/timekeeping.h
@@ -3,9 +3,10 @@
/*
* Internal interfaces for kernel/time/
*/
-extern ktime_t ktime_get_update_offsets_now(ktime_t *offs_real,
- ktime_t *offs_boot,
- ktime_t *offs_tai);
+extern ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq,
+ ktime_t *offs_real,
+ ktime_t *offs_boot,
+ ktime_t *offs_tai);
extern int timekeeping_valid_for_hres(void);
extern u64 timekeeping_max_deferment(void);
next prev parent reply other threads:[~2015-04-14 21:17 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-14 21:08 [patch 00/39] hrtimer/tick: Optimizations, cleanups and solutions for various issues Thomas Gleixner
2015-04-14 21:08 ` [patch 01/39] hrtimer: Update active_bases before calling hrtimer_force_reprogram() Thomas Gleixner
2015-04-14 21:08 ` [patch 02/39] hrtimer: Get rid of the resolution field in hrtimer_clock_base Thomas Gleixner
2015-04-15 6:29 ` Frans Klaver
2015-04-15 6:32 ` Frans Klaver
2015-04-20 8:34 ` Preeti U Murthy
2015-04-22 19:05 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 03/39] net: sched: Use hrtimer_resolution instead of hrtimer_get_res() Thomas Gleixner
2015-04-16 16:04 ` David Miller
2015-04-22 19:05 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 04/39] sound: " Thomas Gleixner
2015-04-16 8:07 ` Takashi Iwai
2015-04-16 9:08 ` Thomas Gleixner
2015-04-22 19:05 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 05/39] hrtimer: Get rid " Thomas Gleixner
2015-04-22 19:05 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 06/39] hrtimer: Make the statistics fields smaller Thomas Gleixner
2015-04-22 19:06 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 07/39] hrtimer: Get rid of softirq time Thomas Gleixner
2015-04-22 19:06 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` Thomas Gleixner [this message]
2015-04-20 9:30 ` [patch 08/39] hrtimer: Make offset update smarter Preeti U Murthy
2015-04-22 19:06 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 09/39] hrtimer: Use a bits for various boolean indicators Thomas Gleixner
2015-04-22 19:07 ` [tip:timers/core] hrtimer: Use " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 10/39] hrtimer: Use cpu_base->active_base for hotpath iterators Thomas Gleixner
2015-04-20 11:16 ` Preeti U Murthy
2015-04-21 11:53 ` Thomas Gleixner
2015-04-22 3:13 ` Preeti U Murthy
2015-04-22 19:07 ` [tip:timers/core] hrtimer: Use cpu_base-> active_base " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 11/39] hrtimer: Cache line align the hrtimer cpu base Thomas Gleixner
2015-04-22 19:07 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 12/39] hrtimer: Align the hrtimer clock bases as well Thomas Gleixner
2015-04-22 19:07 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 13/39] timerqueue: Let timerqueue_add/del return information Thomas Gleixner
2015-04-22 19:08 ` [tip:timers/core] timerqueue: Let timerqueue_add/ del " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 14/39] hrtimer: Make use of timerqueue_add/del return values Thomas Gleixner
2015-04-22 19:08 ` [tip:timers/core] hrtimer: Make use of timerqueue_add/ del " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 15/39] hrtimer: Keep pointer to first timer and simplify __remove_hrtimer() Thomas Gleixner
2015-04-22 19:08 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 16/39] hrtimer: Get rid of hrtimer softirq Thomas Gleixner
2015-04-22 19:09 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 17/39] tick: sched: Remove hrtimer_active() checks Thomas Gleixner
2015-04-16 13:37 ` Frederic Weisbecker
2015-04-22 19:09 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 18/39] tick: sched: Force tick interrupt and get rid of softirq magic Thomas Gleixner
2015-04-22 14:22 ` Frederic Weisbecker
2015-04-22 14:32 ` Thomas Gleixner
2015-04-23 11:47 ` Frederic Weisbecker
2015-04-23 13:07 ` Thomas Gleixner
2015-04-23 16:14 ` Frederic Weisbecker
2015-04-22 19:09 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 19/39] tick: sched: Restructure code Thomas Gleixner
2015-04-22 19:09 ` [tip:timers/core] tick: Sched: " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 20/39] tick: nohz: Rework next timer evaluation Thomas Gleixner
2015-04-16 16:42 ` Paul E. McKenney
2015-04-21 12:04 ` Thomas Gleixner
2015-04-22 19:10 ` [tip:timers/core] tick: Nohz: " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 21/39] x86: perf: Use hrtimer_start() Thomas Gleixner
2015-04-22 19:10 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 22/39] x86: perf: uncore: " Thomas Gleixner
2015-04-22 19:10 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 23/39] perf: core: " Thomas Gleixner
2015-04-22 19:11 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 24/39] sched: core: Use hrtimer_start[_expires]() Thomas Gleixner
2015-04-22 19:11 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 25/39] sched: deadline: Use hrtimer_start() Thomas Gleixner
2015-04-22 19:11 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 26/39] hrtimer: Get rid of __hrtimer_start_range_ns() Thomas Gleixner
2015-04-22 19:11 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 27/39] hrtimer: Make hrtimer_start() a inline wrapper Thomas Gleixner
2015-04-22 19:12 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 28/39] hrtimer: Remove bogus hrtimer_active() check Thomas Gleixner
2015-04-22 19:12 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 29/39] hrtimer: Rmove " Thomas Gleixner
2015-04-22 19:12 ` [tip:timers/core] futex: Remove " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 30/39] rtmutex: " Thomas Gleixner
2015-04-22 19:13 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 31/39] net: core: pktgen: " Thomas Gleixner
2015-04-16 16:04 ` David Miller
2015-04-22 19:13 ` [tip:timers/core] net: core: pktgen: Remove bogus hrtimer_active( ) check tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 32/39] alarmtimer: Get rid of unused return value Thomas Gleixner
2015-04-22 19:13 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 34/39] tick: broadcast-hrtimer: Remove overly clever return value abuse Thomas Gleixner
2015-04-17 10:33 ` Preeti U Murthy
2015-04-22 19:13 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 35/39] hrtimer: Remove hrtimer_start() return value Thomas Gleixner
2015-04-22 19:14 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 36/39] hrtimer: Avoid locking in hrtimer_cancel() if timer not active Thomas Gleixner
2015-04-22 19:14 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 37/39] staging: ozwpan: Remove hrtimer_active() check Thomas Gleixner
2015-04-14 21:09 ` [patch 38/39] timer: Remove pointless return value of do_usleep_range() Thomas Gleixner
2015-04-22 19:14 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 39/39] timer: Put usleep_range into the __sched section Thomas Gleixner
2015-04-22 19:14 ` [tip:timers/core] " tip-bot for Thomas Gleixner
[not found] ` <20150414203503.322172417@linutronix.de>
2015-04-14 21:38 ` [patch 33/39] power: reset: ltc2952: Remove bogus hrtimer_start() return value checks Frans Klaver
2015-04-30 15:49 ` Sebastian Reichel
-- strict thread matches above, loose matches on Subject: below --
2015-04-07 2:10 [PATCH V2 0/2] hrtimer: Iterate only over active clock-bases Viresh Kumar
2015-04-07 2:10 ` [PATCH V2 1/2] hrtimer: update '->active_bases' before calling hrtimer_force_reprogram() Viresh Kumar
2015-04-22 19:04 ` [tip:timers/core] hrtimer: Update active_bases " tip-bot for Viresh Kumar
2015-04-07 2:10 ` [PATCH V2 2/2] hrtimer: Iterate only over active clock-bases Viresh Kumar
2015-04-08 12:10 ` Peter Zijlstra
2015-04-08 20:11 ` Thomas Gleixner
2015-04-09 2:42 ` Viresh Kumar
2015-04-09 6:28 ` [PATCH] hrtimer: Replace cpu_base->active_bases with a direct check of the active list Ingo Molnar
2015-04-09 6:38 ` Ingo Molnar
2015-04-09 6:39 ` [PATCH] hrtimer: Only iterate over active bases in migrate_hrtimers() Ingo Molnar
2015-04-09 6:53 ` [PATCH] hrtimer: Replace timerqueue_getnext() uses with direct access to 'active.next' Ingo Molnar
2015-04-09 7:10 ` [PATCH] hrtimers: Use consistent variable names for timerqueue_node iterations Ingo Molnar
2015-04-09 6:57 ` [PATCH] hrtimer: Replace cpu_base->active_bases with a direct check of the active list Peter Zijlstra
2015-04-09 7:09 ` Ingo Molnar
2015-04-09 7:20 ` Ingo Molnar
2015-04-09 8:58 ` Thomas Gleixner
2015-04-09 8:58 ` Peter Zijlstra
2015-04-09 9:18 ` Thomas Gleixner
2015-04-09 9:31 ` Peter Zijlstra
2015-04-09 9:56 ` Thomas Gleixner
2015-04-13 5:53 ` Preeti U Murthy
2015-04-13 7:53 ` Thomas Gleixner
2015-04-09 8:03 ` Peter Zijlstra
2015-04-09 8:10 ` Ingo Molnar
2015-04-09 8:53 ` Thomas Gleixner
2015-04-09 9:18 ` Ingo Molnar
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