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This a tool to benchmark the latency of GPIO driver, it's able to run 2 kinds of benchmark test: 1, loopback mode 1) apply 2 gpio pins by calling service in gpio RTDM driver like gpio-bcm2835 and gpio-core.c, one is as output, the other is as interrupt 2) call write_rt to send a pulse from output 3) call read_rt to get timestamps recorded in driver (inner loop) 4) also record timespace in user space(outer_loop) outer_loop is inner_loop plus overhead of event wakeup 5) ftrace enable/disable 2, react mode 1) apply 2 gpio pins by calling service in gpio RTDM driver like gpio-bcm2835 and gpio-core.c, one is as ourput, the other is as interrupt 2) call read_rt to wait for a pulse from latency box 3) call write_rt to send a signal back to latency box as a reaction 4) latency box calculates the diff and makes the histogram e.g.: 1) react mode: gpiobench -o 20 -i 21 -c pinctrl-bcm2835 -m 1 -l 1000 2) loopback mode: gpiobench -o 20 -i 21 -c...
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