From 06d9e908b2248f983b186aaf569c58e1430db85d Mon Sep 17 00:00:00 2001 From: "venkatesh.pallipadi@intel.com" Date: Wed, 30 Jul 2008 19:21:44 -0700 Subject: [PATCH] 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 Signed-off-by: Andi Kleen --- drivers/cpuidle/governors/ladder.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c index 27ab3bfe375b..a4bec3f919aa 100644 --- a/drivers/cpuidle/governors/ladder.c +++ b/drivers/cpuidle/governors/ladder.c @@ -98,6 +98,18 @@ 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++;