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Commit 525bbc85 authored by Connor O'Brien's avatar Connor O'Brien Committed by Alistair Strachan
Browse files

ANDROID: cpufreq: times: optimize proc files 



The majority of the time spent reading /proc/uid_time_in_state is due
to seq_printf calls. Use the faster seq_put_* variations instead.

Also skip empty hash buckets in uid_seq_next for a further performance
improvement.

Bug: 111216804
Bug: 127641090
Test: Read /proc/uid_time_in_state and confirm output is sane
Test: Compare read times to confirm performance improvement
Change-Id: If8783b498ed73d2ddb186a49438af41ac5ab9957
Signed-off-by: default avatarConnor O'Brien <connoro@google.com>
parent 866e11d8

drivers/cpufreq/cpufreq_times.c

+14 −8
Original line number Diff line number Diff line
@@ -193,10 +193,12 @@ static void *uid_seq_start(struct seq_file *seq, loff_t *pos) 


static void *uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

	do {

		(*pos)++;



		if (*pos >= HASH_SIZE(uid_hash_table))

			return NULL;

	} while (hlist_empty(&uid_hash_table[*pos]));



	return &uid_hash_table[*pos];

}
@@ -220,7 +222,8 @@ static int uid_time_in_state_seq_show(struct seq_file *m, void *v) 
				if (freqs->freq_table[i] ==

				    CPUFREQ_ENTRY_INVALID)

					continue;

				seq_printf(m, " %d", freqs->freq_table[i]);

				seq_put_decimal_ull(m, " ",

						    freqs->freq_table[i]);

			}

		}

		seq_putc(m, '\n');
@@ -229,13 +232,16 @@ static int uid_time_in_state_seq_show(struct seq_file *m, void *v) 
	rcu_read_lock();



	hlist_for_each_entry_rcu(uid_entry, (struct hlist_head *)v, hash) {

		if (uid_entry->max_state)

			seq_printf(m, "%d:", uid_entry->uid);

		if (uid_entry->max_state) {

			seq_put_decimal_ull(m, "", uid_entry->uid);

			seq_putc(m, ':');

		}

		for (i = 0; i < uid_entry->max_state; ++i) {

			u64 time;

			if (freq_index_invalid(i))

				continue;

			seq_printf(m, " %lu", (unsigned long)nsec_to_clock_t(

					   uid_entry->time_in_state[i]));

			time = nsec_to_clock_t(uid_entry->time_in_state[i]);

			seq_put_decimal_ull(m, " ", time);

		}

		if (uid_entry->max_state)

			seq_putc(m, '\n');