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authorRik van Riel <riel@redhat.com>2015-11-03 17:34:18 -0500
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-11-17 02:24:25 +0100
commita9ceb78bc75ca47972096372ff3d48648b16317a (patch)
treef88f49c389bb931e6b64ccfe49ccf3825fadbd7e /drivers/cpuidle
parent7884084f3bcc98adfbd8b90a2bd6bcf10c4df2cd (diff)
cpuidle,menu: use interactivity_req to disable polling
The menu governor carefully figures out how much time we typically sleep for an estimated sleep interval, or whether there is a repeating pattern going on, and corrects that estimate for the CPU load. Then it proceeds to ignore that information when determining whether or not to consider polling. This is not a big deal on most x86 CPUs, which have very low C1 latencies, and the patch should not have any effect on those CPUs. However, certain CPUs (eg. Atom) have much higher C1 latencies, and it would be good to not waste performance and power on those CPUs if we are expecting a very low wakeup latency. Disable polling based on the estimated interactivity requirement, not on the time to the next timer interrupt. Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/governors/menu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index ecc242a586c9..b1a55731f921 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -330,7 +330,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* We want to default to C1 (hlt), not to busy polling
* unless the timer is happening really really soon.
*/
- if (data->next_timer_us > 20 &&
+ if (interactivity_req > 20 &&
!drv->states[CPUIDLE_DRIVER_STATE_START].disabled &&
dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
data->last_state_idx = CPUIDLE_DRIVER_STATE_START;