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ANDROID: cpufreq: times: optimize proc files

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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: Connor O'Brien <connoro@google.com>
This commit is contained in:
Connor O'Brien
2019-02-20 12:17:48 -08:00
committed by Todd Kjos
parent 0d084d72df
commit fcecefc007
1 changed files with 14 additions and 8 deletions
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22
drivers/cpufreq/cpufreq_times.c
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@@ -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)
{
(*pos)++;
do {
(*pos)++;
if (*pos >= HASH_SIZE(uid_hash_table))
return NULL;
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');