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authorvenkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>2008-07-30 19:21:44 -0700
committerAndi Kleen <ak@linux.intel.com>2008-08-15 21:25:35 +0200
commit06d9e908b2248f983b186aaf569c58e1430db85d (patch)
treea72b6608c6f787df72fe34d1d58f02b4b8d1bef7
parent320eee776357db52d6fcfb11cff985b1976a4595 (diff)
cpuidle: Make ladder governor honor latency requirements fully
ladder governor only honored latency requirement when promoting C-states. Instead. it should check for latency requirement on each idle call, and demote to appropriate C-state when there is a latency requirement change. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
-rw-r--r--drivers/cpuidle/governors/ladder.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 27ab3bfe375..a4bec3f919a 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -99,6 +99,18 @@ static int ladder_select_state(struct cpuidle_device *dev)
/* consider demotion */
if (last_idx > CPUIDLE_DRIVER_STATE_START &&
+ dev->states[last_idx].exit_latency > latency_req) {
+ int i;
+
+ for (i = last_idx - 1; i > CPUIDLE_DRIVER_STATE_START; i--) {
+ if (dev->states[i].exit_latency <= latency_req)
+ break;
+ }
+ ladder_do_selection(ldev, last_idx, i);
+ return i;
+ }
+
+ if (last_idx > CPUIDLE_DRIVER_STATE_START &&
last_residency < last_state->threshold.demotion_time) {
last_state->stats.demotion_count++;
last_state->stats.promotion_count = 0;