[PATCH 3/6 v2] cpufreq: tolerate inexact values when collecting stats

Mark Langsdorf
2012-11-02T18:52:56Z

When collecting stats, if a frequency doesn't match the table, go through
the table again with both the search frequency and table values shifted
left by 10 bits.

Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
Cc: MyungJoo Ham <myungjoo.ham@gmail.com>

Changes from v1:
Implemented a simple round-up algorithm instead of the over/under
method that could cause errors on Intel processors with boost mode.
---
drivers/cpufreq/cpufreq_stats.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 3998316..ab583e7 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -158,8 +158,12 @@ static struct attribute_group stats_attr_group = {
static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
{
int index;
+ for (index = 0; index < stat->max_state; index++)
+ if (stat->freq_table[index] == freq)
+ return index;
+ /* no exact match, round up */
for (index = 0; index < stat->max_state; index++)
- if (stat->freq_table[index] == freq)
+ if ((stat->freq_table[index] >> 10) == (freq >> 10))
return index;
return -1;
}
@@ -251,6 +255,8 @@ static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
spin_lock(&cpufreq_stats_lock);
stat->last_time = get_jiffies_64();
stat->last_index = freq_table_get_index(stat, policy->cur);
+ if (stat->last_index > stat->max_state)
+ stat->last_index = stat->max_state - 1;
spin_unlock(&cpufreq_stats_lock);
cpufreq_cpu_put(data);
return 0;
--
1.7.11.7