linux-kernel - [PATCH 3/4] cpuidle/menu: stop seeking deeper idle if current state is too deep

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Message-Id: <1471595114-1688-3-git-send-email-alex.shi@linaro.org>
Date:   Fri, 19 Aug 2016 16:25:13 +0800
From:   Alex Shi <alex.shi@...aro.org>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Rik van Riel <riel@...hat.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 3/4] cpuidle/menu: stop seeking deeper idle if current state is too deep

The obsolete commit 71abbbf85 want to introduce a dynamic cstates,
but it was removed for long time. Just left the nonsense deeper cstate
checking.

Since all target_residency and exit_latency are going longer in deeper
idle state, no needs to waste some cpu cycle on useless seeking.

Signed-off-by: Alex Shi <alex.shi@...aro.org>
To: linux-kernel@...r.kernel.org
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Rasmus Villemoes <linux@...musvillemoes.dk>
Cc: Alex Shi <alex.shi@...aro.org>
Cc: Arjan van de Ven <arjan@...ux.intel.com>
Cc: Rik van Riel <riel@...hat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
---
 drivers/cpuidle/governors/menu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 03d38c2..bb58e2a 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -358,9 +358,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 		if (s->disabled || su->disable)
 			continue;
 		if (s->target_residency > data->predicted_us)
-			continue;
+			break;
 		if (s->exit_latency > latency_req)
-			continue;
+			break;
 
 		data->last_state_idx = i;
 	}
-- 
2.8.1.101.g72d917a