diff mbox

[1/3] cpuidle/menu: stop seeking deeper idle if current state is too deep

Message ID 1483630187-29622-2-git-send-email-alex.shi@linaro.org
State Superseded
Headers show

Commit Message

Alex Shi Jan. 5, 2017, 3:29 p.m. UTC
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@linaro.org>

To: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
---
 drivers/cpuidle/governors/menu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.8.1.101.g72d917a

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Comments

Rik van Riel Jan. 5, 2017, 3:43 p.m. UTC | #1
On Thu, 2017-01-05 at 23:29 +0800, Alex Shi wrote:
> 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.


Makes me wonder if it would be worth documenting the
requirement that c-states be listed in increasing
order?

Acked-by: Rik van Riel <riel@redhat.com>

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Arjan van de Ven Jan. 5, 2017, 3:55 p.m. UTC | #2
On 1/5/2017 7:43 AM, Rik van Riel wrote:
> On Thu, 2017-01-05 at 23:29 +0800, Alex Shi wrote:

>> 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.

>

> Makes me wonder if it would be worth documenting the

> requirement that c-states be listed in increasing

> order?


or better, a boot time quick check...

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diff mbox

Patch

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index d9b5b93..07e36bb 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -357,9 +357,9 @@  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;
 	}