Hey, I am trying to use GPIO as input trigger to my system. I am using shell command before I am running my code: echo in >/sys/class/gpio/gpio443/direction echo falling >/sys/class/gpio/gpio443/edge and also a C code: void gpio_test() { if ((fd = open("/sys/class/gpio/gpio443/value", O_RDWR)) < 0) { fprintf(stderr, "Failed, gpio %d not exported.\n", gpioPin); return -1; } pfd.fd = fd; pfd.events = POLLPRI; lseek(fd, 0, SEEK_SET); /* consume any prior interrupt */ read(fd, buf, sizeof(buf)); rc = poll(&pfd, 1, timeoutMS); /* wait for interrupt */ if (rc < 0) strerror(errno); lseek(fd, 0, SEEK_SET); /* consume interrupt */ read(fd, buf, sizeof(buf)); } I see that the interrupt arrived with ~15 ms latency after the GPIO fall down. The program runs in user space. There is any way to decrease the latency?

There is no update from you for a period, assuming this is not an issue any more. Hence we are closing this topic. If need further support, please open a new one. Thanks hello almog1, would you please use $ nice to set higher process priority to confirm the behavior? thanks

Hey Jerry, I have tried to use attached commands: sudo su cat /sys/kernel/debug/bpmp/debug/clk/axi_cbb/max_rate # 408000000 cat /sys/kernel/debug/bpmp/debug/clk/axi_cbb/max_rate > /sys/kernel/debug/bpmp/debug/clk/axi_cbb/rate echo 1 > /sys/kernel/debug/bpmp/debug/clk/axi_cbb/mrq_rate_locked cat /sys/kernel/debug/bpmp/debug/clk/axi_cbb/rate # 408000000 cat /sys/kernel/debug/bpmp/debug/clk/axi_cbb/max_rate # 408000000 cat /sys/kernel/debug/bpmp/debug/clk/axi_cbb/mrq_rate_locked # 1 I am still get the interrupt with ~15ms latency. root@nvidia:/home/nvidia# cat /proc/interrupts | grep gpiolib 353: 8767 0 0 0 0 0 0 0 tegra-gpio 155 Edge gpiolib

[image] almog1: I am still get the interrupt with ~15ms latency. may I know how you evaluate 15ms latency, are you probing the signal or adding kernel logs to check the timestamp?

Hey Jerry, You right, Actually I have checked it via log file. In case of checking it with oscilloscope it actually works fine. Thank you

GPIO Interrupt latency

Robotics & Edge Computing Jetson Systems Jetson AGX Xavier

JerryChang December 10, 2021, 6:09am 3

hello almog1,

could you please check Topic 192147 for the steps to improve GPIO interrupt performance.
thanks

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GPIO Interrupt latency

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