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1efba35afa
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>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.