gpio: sysfs: avoid using kstrtol() in 'value' attribute write
A 'perf record' on an app continuously writing in the 'value'
attribute show that most of the time is spent in kstrtol()
--17.99%--value_store
|
|--10.17%--kstrtoint
| |
| |--8.82%--kstrtoll
|
|--2.50%--gpiod_set_value_cansleep
|
|--1.82%--u16_gpio_set
|
|--1.46%--value_store
The normal case is to write 0 or 1 in the attribute, therefore
this patch avoids the call to kstrtol() in the most common cases
Then 'perf record' shows
--7.21%--value_store
|
|--2.69%--u16_gpio_set
|
|--1.47%--value_store
|
|--1.08%--gpiod_set_value_cansleep
|
|--0.60%--mutex_lock
|
--0.58%--mutex_unlock
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
1 file changed