Linux

GPIO

Export pin

echo 2 > /sys/class/gpio/export

Set pin

echo "out" > /sys/class/gpio/gpio2/direction
echo 1 > /sys/class/gpio/gpio2/value
echo 0 > /sys/class/gpio/gpio2/value

Read pin

echo "in" > /sys/class/gpio/gpio2/direction
cat /sys/class/gpio/gpio2/value

Verify using debugfs

mount -t debugfs none /sys/kernel/debug
cat /sys/kernel/debug/gpio

Performance Tools

Performance Analysis

BPF Performance Tools

• http://www.brendangregg.com/bpf-performance-tools-book.html