diff mbox series

[v2,01/25] timekeeping: Read NTP tick length only once

Message ID 20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-1-554456a44a15@linutronix.de (mailing list archive)
State Not Applicable
Headers show
Series timekeeping: Rework to prepare support of indenpendent PTP clocks | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Anna-Maria Behnsen Oct. 9, 2024, 8:28 a.m. UTC 
From: Thomas Gleixner <tglx@linutronix.de>

From: Thomas Gleixner <tglx@linutronix.de>

No point in reading it a second time when the comparison fails.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
 kernel/time/timekeeping.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

John Stultz Oct. 9, 2024, 5:18 p.m. UTC | #1 
On Wed, Oct 9, 2024 at 1:29 AM Anna-Maria Behnsen
<anna-maria@linutronix.de> wrote:
>
> From: Thomas Gleixner <tglx@linutronix.de>
>
> From: Thomas Gleixner <tglx@linutronix.de>
>
> No point in reading it a second time when the comparison fails.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>

Acked-by: John Stultz <jstultz@google.com>
diff mbox series

Patch

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 7e6f409bf311..6acff4cb7b1c 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -2130,16 +2130,17 @@  static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
  */
 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
 {
+	u64 ntp_tl = ntp_tick_length();
 	u32 mult;
 
 	/*
 	 * Determine the multiplier from the current NTP tick length.
 	 * Avoid expensive division when the tick length doesn't change.
 	 */
-	if (likely(tk->ntp_tick == ntp_tick_length())) {
+	if (likely(tk->ntp_tick == ntp_tl)) {
 		mult = tk->tkr_mono.mult - tk->ntp_err_mult;
 	} else {
-		tk->ntp_tick = ntp_tick_length();
+		tk->ntp_tick = ntp_tl;
 		mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
 				 tk->xtime_remainder, tk->cycle_interval);
 	}