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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: John Stultz <john.stultz@linaro.org>, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	Eric Dumazet <dada1@cosmosbay.com>,
	Frederic Weisbecker <fweisbec@gmail.com>
Subject: [RFC patch 1/8] timekeeping: Calc stuff once
Date: Thu, 21 Feb 2013 22:51:36 -0000	[thread overview]
Message-ID: <20130221224230.765526400@linutronix.de> (raw)
In-Reply-To: 20130221220147.719832397@linutronix.de

[-- Attachment #1: timekeeping-do-not-calc-crap-over-and-over.patch --]
[-- Type: text/plain, Size: 1123 bytes --]

Calculate the cycle interval shifted value once. No functional change,
just makes the code more readable.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/timekeeping.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Index: linux-2.6/kernel/time/timekeeping.c
===================================================================
--- linux-2.6.orig/kernel/time/timekeeping.c
+++ linux-2.6/kernel/time/timekeeping.c
@@ -1102,15 +1102,16 @@ static inline void accumulate_nsecs_to_s
 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
 						u32 shift)
 {
+	cycle_t interval = tk->cycle_interval << shift;
 	u64 raw_nsecs;
 
 	/* If the offset is smaller then a shifted interval, do nothing */
-	if (offset < tk->cycle_interval<<shift)
+	if (offset < interval)
 		return offset;
 
 	/* Accumulate one shifted interval */
-	offset -= tk->cycle_interval << shift;
-	tk->clock->cycle_last += tk->cycle_interval << shift;
+	offset -= interval;
+	tk->clock->cycle_last += interval;
 
 	tk->xtime_nsec += tk->xtime_interval << shift;
 	accumulate_nsecs_to_secs(tk);



  reply	other threads:[~2013-02-21 22:51 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-21 22:51 [RFC patch 0/8] timekeeping: Implement shadow timekeeper to shorten in kernel reader side blocking Thomas Gleixner
2013-02-21 22:51 ` Thomas Gleixner [this message]
2013-02-21 22:51 ` [RFC patch 2/8] timekeeping: Make jiffies_lock internal Thomas Gleixner
2013-02-21 22:51 ` [RFC patch 3/8] timekeeping: Move lock out of timekeeper struct Thomas Gleixner
2013-02-21 22:51 ` [RFC patch 5/8] timekeeping: Store cycle_last value in timekeeper struct as well Thomas Gleixner
2013-02-21 22:51 ` [RFC patch 4/8] timekeeping: Split timekeeper_lock into lock and seqcount Thomas Gleixner
2013-02-21 22:51 ` [RFC patch 6/8] timekeeping: Delay update of clock->cycle_last Thomas Gleixner
2013-02-21 22:51 ` [RFC patch 8/8] timekeeping: Shorten seq_count region Thomas Gleixner
2013-02-21 22:51 ` [RFC patch 7/8] timekeeping: Implement a shadow timekeeper Thomas Gleixner
2013-02-22 23:53   ` John Stultz
2013-02-26 12:17     ` Thomas Gleixner
2013-02-21 23:06 ` [RFC patch 0/8] timekeeping: Implement shadow timekeeper to shorten in kernel reader side blocking Eric Dumazet

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