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| author | Liao Chang <liaochang1@huawei.com> | 2023-08-18 12:50:00 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-08-21 21:57:30 +0300 |
| commit | ed9571647eff3dd7a53068f83338530959c7ace4 (patch) | |
| tree | bd99cd42e483e6d12246441c72b2c3187fc7256a /drivers/cpufreq | |
| parent | 706a741595047797872e669b3101429ab8d378ef (diff) | |
| download | linux-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.c | 3 |
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; |