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| author | venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com> | 2008-07-30 19:21:44 -0700 |
|---|---|---|
| committer | Andi Kleen <ak@linux.intel.com> | 2008-08-15 21:25:35 +0200 |
| commit | 06d9e908b2248f983b186aaf569c58e1430db85d (patch) | |
| tree | a72b6608c6f787df72fe34d1d58f02b4b8d1bef7 /drivers/cpuidle | |
| parent | 320eee776357db52d6fcfb11cff985b1976a4595 (diff) | |
| download | lwn-06d9e908b2248f983b186aaf569c58e1430db85d.tar.gz lwn-06d9e908b2248f983b186aaf569c58e1430db85d.zip | |
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>
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/governors/ladder.c | 12 |
1 files changed, 12 insertions, 0 deletions
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 @@ -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; |