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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Christian Loehle <christian.loehle@arm.com>,
	Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Subject: [PATCH v1 4/9] cpuidle: teo: Drop local variable prev_intercept_idx
Date: Mon, 13 Jan 2025 19:40:49 +0100	[thread overview]
Message-ID: <3327997.aeNJFYEL58@rjwysocki.net> (raw)
In-Reply-To: <6116275.lOV4Wx5bFT@rjwysocki.net>

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

Local variable prev_intercept_idx in teo_select() is redundant becase
it cannot be 0 when candidate state index is 0.

The prev_intercept_idx value is the index of the deepest enabled idle
state, so if it is 0, state 0 is the deepest enabled idle state, in
which case it must be the only enabled idle state, but then teo_select()
would have returned early before initializing prev_intercept_idx.

Thus prev_intercept_idx must be nonzero and the check of it against 0
always passes, so it can be dropped altogether.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpuidle/governors/teo.c |   15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

--- a/drivers/cpuidle/governors/teo.c
+++ b/drivers/cpuidle/governors/teo.c
@@ -292,7 +292,6 @@
 	unsigned int hit_sum = 0;
 	int constraint_idx = 0;
 	int idx0 = 0, idx = -1;
-	int prev_intercept_idx;
 	s64 duration_ns;
 	int i;
 
@@ -370,7 +369,6 @@
 	 * all of the deeper states, a shallower idle state is likely to be a
 	 * better choice.
 	 */
-	prev_intercept_idx = idx;
 	if (2 * idx_intercept_sum > cpu_data->total - idx_hit_sum) {
 		int first_suitable_idx = idx;
 
@@ -437,14 +435,11 @@
 		idx = constraint_idx;
 
 	if (!idx) {
-		if (prev_intercept_idx) {
-			/*
-			 * Query the sleep length to be able to count the wakeup
-			 * as a hit if it is caused by a timer.
-			 */
-			duration_ns = tick_nohz_get_sleep_length(&delta_tick);
-			cpu_data->sleep_length_ns = duration_ns;
-		}
+		/*
+		 * Query the sleep length to be able to count the wakeup as a
+		 * hit if it is caused by a timer.
+		 */
+		cpu_data->sleep_length_ns = tick_nohz_get_sleep_length(&delta_tick);
 		goto out_tick;
 	}
 




  parent reply	other threads:[~2025-01-13 18:52 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-13 18:32 [PATCH v1 0/9] cpuidle: teo: Cleanups and very frequent wakeups handling update Rafael J. Wysocki
2025-01-13 18:34 ` [PATCH v1 1/9] cpuidle: teo: Rearrange idle state lookup code Rafael J. Wysocki
2025-01-15 14:21   ` Christian Loehle
2025-01-13 18:36 ` [PATCH v1 2/9] cpuidle: teo: Reorder candidate state index checks Rafael J. Wysocki
2025-01-15 14:46   ` Christian Loehle
2025-01-15 15:54     ` Rafael J. Wysocki
2025-01-15 19:20       ` Christian Loehle
2025-01-15 20:48         ` Rafael J. Wysocki
2025-01-15 21:10           ` Rafael J. Wysocki
2025-01-16 12:22             ` Rafael J. Wysocki
2025-01-16 13:26               ` Christian Loehle
2025-01-16 13:27   ` Christian Loehle
2025-01-13 18:39 ` [PATCH v1 3/9] cpuidle: teo: Combine candidate state index checks against 0 Rafael J. Wysocki
2025-01-15 19:44   ` Christian Loehle
2025-01-13 18:40 ` Rafael J. Wysocki [this message]
2025-01-15 19:46   ` [PATCH v1 4/9] cpuidle: teo: Drop local variable prev_intercept_idx Christian Loehle
2025-01-13 18:41 ` [PATCH v1 5/9] cpuidle: teo: Clarify two code comments Rafael J. Wysocki
2025-01-15 19:43   ` Christian Loehle
2025-01-13 18:45 ` [PATCH v1 6/9] cpuidle: teo: Simplify counting events used for tick management Rafael J. Wysocki
2025-01-20 11:27   ` Christian Loehle
2025-01-13 18:48 ` [PATCH v1 7/9] cpuidle: teo: Skip getting the sleep length is wakeups are very frequent Rafael J. Wysocki
2025-01-20 12:08   ` Christian Loehle
2025-01-20 16:24     ` Rafael J. Wysocki
2025-01-13 18:50 ` [PATCH v1 8/9] cpuidle: teo: Simplify handling of total events count Rafael J. Wysocki
2025-01-20 12:10   ` Christian Loehle
2025-01-13 18:51 ` [PATCH v1 9/9] cpuidle: teo: Replace time_span_ns with a flag Rafael J. Wysocki
2025-01-20 12:16   ` Christian Loehle
2025-01-20 12:42     ` Rafael J. Wysocki
2025-01-15 14:52 ` [PATCH v1 0/9] cpuidle: teo: Cleanups and very frequent wakeups handling update Christian Loehle
2025-01-20  8:17   ` Aboorva Devarajan
2025-01-20 16:26     ` Rafael J. Wysocki
2025-01-20 16:24   ` Rafael J. Wysocki

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