linux-kernel - [PATCH v1] cpuidle: teo: Avoid unnecessary variable assignments

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Message-ID: <12275754.O9o76ZdvQC@kreacher>
Date:   Tue, 22 Aug 2023 13:28:02 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Anna-Maria Behnsen <anna-maria@...utronix.de>,
        Doug Smythies <dsmythies@...us.net>,
        Kajetan Puchalski <kajetan.puchalski@....com>,
        Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH v1] cpuidle: teo: Avoid unnecessary variable assignments

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Notice that it is not necessary to assign tick_intercept_sum in every
iteration of the first loop over idle states in teo_select(), because
the intercept_sum value does not change after the assignment in a
given iteration of the loop, so its value after the last iteration of
the loop can be used for computing the tick_intercept_sum value
directly.

Modify the code accordingly.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

This is based on the pm-cpuidle-gov branch in linux-pm.git (which is included
into linux-next too).

---
 drivers/cpuidle/governors/teo.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/cpuidle/governors/teo.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/governors/teo.c
+++ linux-pm/drivers/cpuidle/governors/teo.c
@@ -450,8 +450,6 @@ static int teo_select(struct cpuidle_dri
 		hit_sum += prev_bin->hits;
 		recent_sum += prev_bin->recent;
 
-		tick_intercept_sum = intercept_sum;
-
 		if (dev->states_usage[i].disable)
 			continue;
 
@@ -484,7 +482,8 @@ static int teo_select(struct cpuidle_dri
 		goto end;
 	}
 
-	tick_intercept_sum += cpu_data->state_bins[drv->state_count-1].intercepts;
+	tick_intercept_sum = intercept_sum +
+			cpu_data->state_bins[drv->state_count-1].intercepts;
 
 	/*
 	 * If the sum of the intercepts metric for all of the idle states