> > > > Felipe, I use Dynamic Debug for debugging, and show debug messages > > with "dmesg" after testing/debugging. I see dwc3 using trace, any > > benefits for switching to trace? > > The benefits I see are >
Thanks, bin. > - *by default*, the debug log doesn't have to go through uart console, > which is slow. > > I typically 'cat trace_pipe' from a telnet which is much faster then > uart. But Dynamic Debug log by default got printed on uart, I have to > set printk level to not print them, which is an extra step. > It depends on the rootfs's setting. By default, the debug message level should be off ( console level = 7) > - tracepoint uses one place to decode the message vs DD has to repeat > the similar print statement in the code; and tracepoint decodes it > offline which reduce the kernel runtime overhead too. > offline? You mean when you run "cat trace_pipe"? > - with tracepoint, it is easier to turn on debug for a specific group of > messages. > The DD can, but we don't do it often. https://www.kernel.org/doc/html/latest/admin-guide/dynamic-debug-howto.html?highlight=dynamic%20debug > - you can adjust the ftrace buffer size at runtime. can we do that for > printk? I don't remember. It may can't. The log buf can only be changed by bootargs: log_buf_len Peter
