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authorChristophe Leroy <christophe.leroy@c-s.fr>2017-12-18 13:08:35 +0300
committerLinus Walleij <linus.walleij@linaro.org>2017-12-20 12:34:58 +0300
commit1efba35afae43094d3f26093f5f1ab8a46686a6f (patch)
tree5f0cc54ea8cd6826f8daa5d17410b7c9e6f19f8f /tools/gpio/gpio-event-mon.c
parent7a94b88cb7087aa3184161bedccfea25e5502c62 (diff)
downloadlinux-1efba35afae43094d3f26093f5f1ab8a46686a6f.tar.xz
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>
Diffstat (limited to 'tools/gpio/gpio-event-mon.c')
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