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authorLiao Chang <liaochang1@huawei.com>2023-08-18 12:50:00 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-08-21 21:57:30 +0300
commited9571647eff3dd7a53068f83338530959c7ace4 (patch)
treebd99cd42e483e6d12246441c72b2c3187fc7256a /drivers/cpufreq
parent706a741595047797872e669b3101429ab8d378ef (diff)
downloadlinux-ed9571647eff3dd7a53068f83338530959c7ace4.tar.xz
cpufreq: stats: Improve the performance of cpufreq_stats_create_table()
In the worst case, the freq_table of policy data is not sorted and contains duplicate frequencies, this means that it needs to iterate through the entire freq_table of policy to ensure each frequency is unique in the freq_table of stats data, this has a time complexity of O(N^2), where N is the number of frequencies in the freq_table of policy. However, if the policy.freq_table is already sorted and contains no duplicate frequencies, it can reduce the time complexity of creating stats.freq_table to O(N), the 'freq_table_sorted' field of policy data can be used to indicate whether the policy.freq_table is sorted. Signed-off-by: Liao Chang <liaochang1@huawei.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Dhruva Gole <d-gole@ti.com> [ rjw: Fix typo in changelog, remove redundant parens ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq_stats.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 55c7ffd37d1c..a33df3c66c88 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -243,7 +243,8 @@ void cpufreq_stats_create_table(struct cpufreq_policy *policy)
/* Find valid-unique entries */
cpufreq_for_each_valid_entry(pos, policy->freq_table)
- if (freq_table_get_index(stats, pos->frequency) == -1)
+ if (policy->freq_table_sorted != CPUFREQ_TABLE_UNSORTED ||
+ freq_table_get_index(stats, pos->frequency) == -1)
stats->freq_table[i++] = pos->frequency;
stats->state_num = i;