Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Mon, 21 Aug 2023 21:00:24 +0200 | Subject | Re: [PATCH] cpufreq: stats: Improve the performance of cpufreq_stats_create_table() |
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On Mon, Aug 21, 2023 at 11:14 AM Dhruva Gole <d-gole@ti.com> wrote: > > On Aug 18, 2023 at 09:50:00 +0000, Liao Chang wrote: > > 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 frequencices, it can reduce the time complexity of creating > > s/frequencices/frequencies?
I've fixed this when applying the patch.
> > 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> > > --- > > drivers/cpufreq/cpufreq_stats.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c > > index 55c7ffd37d1c..fcb74050711a 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) ||
I've also removed the redundant parens from this check.
> > [...] > > Otherwise looks okay to me, > > Reviewed-by: Dhruva Gole <d-gole@ti.com>
Applied as 6.6 material (with the changes mentioned above), thanks!
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