[PATCH 3/6 v4] cpufreq: tolerate inexact values when collecting stats

Mark Langsdorf
2012-11-07T18:32:43Z

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 v3, v2
None
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 | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 3998316..30aee36 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -161,6 +161,9 @@ static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
for (index = 0; index < stat->max_state; index++)
if (stat->freq_table[index] == freq)
return index;
+ for (index = 0; index < stat->max_state; index++)
+ if ((stat->freq_table[index] >> 10) == (freq >> 10))
+ return index;
return -1;
}

@@ -251,6 +254,8 @@ 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