ftrace调试经验

基础命令

#如果没有mount debugfs,否则跳过
mkdir /debugfs
mount -t debugfs nodev debugfs/
cd debugfs/tracing/

cd /sys/kernel/debug/tracing

echo > /sys/kernel/debug/tracing/trace
echo > /sys/kernel/debug/tracing/set_ftrace_filter
echo funcgraph-proc > trace_options
echo function_graph > /sys/kernel/debug/tracing/current_tracer
echo kvm_vcpu_ioctl *pl011* > set_ftrace_filter
echo 'kvm:*' 'irq:irq_handler_entry' 'irq:irq_handler_exit' 'sched:*' > /sys/kernel/debug/tracing/set_event

echo 1 > /sys/kernel/debug/tracing/tracing_on
cd ~/
taskset 0x0080 qemu-system-aarch64 -m 1024 -cpu host -M virt -smp 1 -nographic -kernel Image -initrd mini-rootfs-arm64.cpio.gz --enable-kvm &
iperf -c 192.168.11.2
echo 0 > /sys/kernel/debug/tracing/tracing_on  
cat  /sys/kernel/debug/tracing/trace > ~/trace.log
cat ~/trace.log