From: Alex Shi <alex.shi@linaro.org>
To: linux-kernel@vger.kernel.org (open list)
Cc: linux-pm@vger.kernel.org, Ulf Hansson <ulf.hansson@linaro.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Arjan van de Ven <arjan@linux.intel.com>,
Rik van Riel <riel@redhat.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: [PATCH 4/4] cpuidle/menu: add per cpu pm_qos_resume_latency consideration
Date: Thu, 25 Aug 2016 16:42:42 +0800 [thread overview]
Message-ID: <1472114562-2736-4-git-send-email-alex.shi@linaro.org> (raw)
In-Reply-To: <1472114562-2736-1-git-send-email-alex.shi@linaro.org>
Kernel or user may have special requirement on cpu response time, like
if a interrupt is pinned to a cpu, we don't want the cpu goes too deep
sleep. This patch can prevent this thing happen by consider per cpu
resume_latency setting in cpu sleep state selection in menu governor.
The pm_qos_resume_latency ask device to give reponse in this time. That's
similar with cpu cstates' entry_latency + exit_latency. But since
most of cpu cstate either has no entry_latency or add it into exit_latency
So, we just can restrict this time requirement as states exit_latency.
The 0 value of pm_qos_resume_latency is for no limitation according ABI
definition. So set the value 1 could get the 0 latency if it's needed.
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: Alex Shi <alex.shi@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>
---
| 7 +++++++
1 file changed, 7 insertions(+)
--git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index bb58e2a..e354880 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -12,6 +12,7 @@
#include <linux/kernel.h>
#include <linux/cpuidle.h>
+#include <linux/cpu.h>
#include <linux/pm_qos.h>
#include <linux/time.h>
#include <linux/ktime.h>
@@ -281,17 +282,23 @@ again:
static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
struct menu_device *data = this_cpu_ptr(&menu_devices);
+ struct device *device = get_cpu_device(dev->cpu);
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
int i;
unsigned int interactivity_req;
unsigned int expected_interval;
unsigned long nr_iowaiters, cpu_load;
+ int resume_latency = dev_pm_qos_read_value(device);
if (data->needs_update) {
menu_update(drv, dev);
data->needs_update = 0;
}
+ /* resume_latency is 0 means no restriction */
+ if (resume_latency && resume_latency < latency_req)
+ latency_req = resume_latency;
+
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0))
return 0;
--
2.8.1.101.g72d917a
next prev parent reply other threads:[~2016-08-25 8:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-25 8:42 [PATCH 1/4] cpu: clean up register_cpu func Alex Shi
2016-08-25 8:42 ` [PATCH 2/4] cpu: expose pm_qos_resume_latency for each cpu Alex Shi
2016-08-31 10:45 ` Alex Shi
2016-08-31 13:18 ` Greg Kroah-Hartman
2016-09-01 3:39 ` Alex Shi
2016-09-01 3:45 ` Alex Shi
2016-09-01 3:50 ` Alex Shi
2016-09-01 9:26 ` Ulf Hansson
2016-09-13 1:04 ` Alex Shi
2016-09-13 7:17 ` Ulf Hansson
2016-09-13 13:57 ` Alex Shi
2016-08-25 8:42 ` [PATCH 3/4] cpuidle/menu: stop seeking deeper idle if current state is too deep Alex Shi
2016-08-31 10:45 ` Alex Shi
2016-09-13 14:01 ` Alex Shi
2016-08-25 8:42 ` Alex Shi [this message]
2016-08-31 10:46 ` [PATCH 4/4] cpuidle/menu: add per cpu pm_qos_resume_latency consideration Alex Shi
2016-09-13 14:02 ` Alex Shi
2016-09-13 22:10 ` Rafael J. Wysocki
2016-09-14 8:28 ` Vincent Guittot
2016-09-23 1:36 ` Rafael J. Wysocki
2016-09-23 4:58 ` Alex Shi
2016-08-31 10:45 ` [PATCH 1/4] cpu: clean up register_cpu func Alex Shi
2016-08-31 13:17 ` Greg Kroah-Hartman
-- strict thread matches above, loose matches on Subject: below --
2016-08-19 8:25 Alex Shi
2016-08-19 8:25 ` [PATCH 4/4] cpuidle/menu: add per cpu pm_qos_resume_latency consideration Alex Shi
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